def __init__(self, region_name):
     super(SNSBackend, self).__init__()
     self.topics = OrderedDict()
     self.subscriptions = OrderedDict()
     self.applications = {}
     self.platform_endpoints = {}
     self.region_name = region_name

 def __init__(self, ec2_backend, elb_backend, elbv2_backend):
     self.autoscaling_groups = OrderedDict()
     self.launch_configurations = OrderedDict()
     self.policies = {}
     self.ec2_backend = ec2_backend
     self.elb_backend = elb_backend
     self.elbv2_backend = elbv2_backend

class Shard(BaseModel):

    def __init__(self, shard_id, starting_hash, ending_hash):
        self._shard_id = shard_id
        self.starting_hash = starting_hash
        self.ending_hash = ending_hash
        self.records = OrderedDict()

    @property
    def shard_id(self):
        return "shardId-{0}".format(str(self._shard_id).zfill(12))

    def get_records(self, last_sequence_id, limit):
        last_sequence_id = int(last_sequence_id)
        results = []

        for sequence_number, record in self.records.items():
            if sequence_number > last_sequence_id:
                results.append(record)
                last_sequence_id = sequence_number

            if len(results) == limit:
                break

        return results, last_sequence_id

    def put_record(self, partition_key, data, explicit_hash_key):
        # Note: this function is not safe for concurrency
        if self.records:
            last_sequence_number = self.get_max_sequence_number()
        else:
            last_sequence_number = 0
        sequence_number = last_sequence_number + 1
        self.records[sequence_number] = Record(
            partition_key, data, sequence_number, explicit_hash_key)
        return sequence_number

    def get_min_sequence_number(self):
        if self.records:
            return list(self.records.keys())[0]
        return 0

    def get_max_sequence_number(self):
        if self.records:
            return list(self.records.keys())[-1]
        return 0

    def to_json(self):
        return {
            "HashKeyRange": {
                "EndingHashKey": str(self.ending_hash),
                "StartingHashKey": str(self.starting_hash)
            },
            "SequenceNumberRange": {
                "EndingSequenceNumber": self.get_max_sequence_number(),
                "StartingSequenceNumber": self.get_min_sequence_number(),
            },
            "ShardId": self.shard_id
        }

class FakeTargetGroup(BaseModel):
    def __init__(self,
                 name,
                 arn,
                 vpc_id,
                 protocol,
                 port,
                 healthcheck_protocol,
                 healthcheck_port,
                 healthcheck_path,
                 healthcheck_interval_seconds,
                 healthcheck_timeout_seconds,
                 healthy_threshold_count,
                 unhealthy_threshold_count):
        self.name = name
        self.arn = arn
        self.vpc_id = vpc_id
        self.protocol = protocol
        self.port = port
        self.healthcheck_protocol = healthcheck_protocol
        self.healthcheck_port = healthcheck_port
        self.healthcheck_path = healthcheck_path
        self.healthcheck_interval_seconds = healthcheck_interval_seconds
        self.healthcheck_timeout_seconds = healthcheck_timeout_seconds
        self.healthy_threshold_count = healthy_threshold_count
        self.unhealthy_threshold_count = unhealthy_threshold_count
        self.load_balancer_arns = []
        self.tags = {}

        self.attributes = {
            'deregistration_delay.timeout_seconds': 300,
            'stickiness.enabled': 'false',
        }

        self.targets = OrderedDict()

    def register(self, targets):
        for target in targets:
            self.targets[target['id']] = {
                'id': target['id'],
                'port': target.get('port', self.port),
            }

    def deregister(self, targets):
        for target in targets:
            t = self.targets.pop(target['id'], None)
            if not t:
                raise InvalidTargetError()

    def add_tag(self, key, value):
        if len(self.tags) >= 10 and key not in self.tags:
            raise TooManyTagsError()
        self.tags[key] = value

    def health_for(self, target):
        t = self.targets.get(target['id'])
        if t is None:
            raise InvalidTargetError()
        return FakeHealthStatus(t['id'], t['port'], self.healthcheck_port, 'healthy')

 def __init__(self, region_name):
     super(SNSBackend, self).__init__()
     self.topics = OrderedDict()
     self.subscriptions = OrderedDict()
     self.applications = {}
     self.platform_endpoints = {}
     self.region_name = region_name
     self.sms_attributes = {}
     self.opt_out_numbers = ['+447420500600', '+447420505401', '+447632960543', '+447632960028', '+447700900149', '+447700900550', '+447700900545', '+447700900907']
     self.permissions = {}

class SNSBackend(BaseBackend):
    def __init__(self):
        self.topics = OrderedDict()
        self.subscriptions = OrderedDict()

    def create_topic(self, name):
        topic = Topic(name, self)
        self.topics[topic.arn] = topic
        return topic

    def _get_values_nexttoken(self, values_map, next_token=None):
        if next_token is None:
            next_token = 0
        next_token = int(next_token)
        values = list(values_map.values())[next_token: next_token + DEFAULT_PAGE_SIZE]
        if len(values) == DEFAULT_PAGE_SIZE:
            next_token = next_token + DEFAULT_PAGE_SIZE
        else:
            next_token = None
        return values, next_token

    def list_topics(self, next_token=None):
        return self._get_values_nexttoken(self.topics, next_token)

    def delete_topic(self, arn):
        self.topics.pop(arn)

    def get_topic(self, arn):
        return self.topics[arn]

    def set_topic_attribute(self, topic_arn, attribute_name, attribute_value):
        topic = self.get_topic(topic_arn)
        setattr(topic, attribute_name, attribute_value)

    def subscribe(self, topic_arn, endpoint, protocol):
        topic = self.get_topic(topic_arn)
        subscription = Subscription(topic, endpoint, protocol)
        self.subscriptions[subscription.arn] = subscription
        return subscription

    def unsubscribe(self, subscription_arn):
        self.subscriptions.pop(subscription_arn)

    def list_subscriptions(self, topic_arn=None, next_token=None):
        if topic_arn:
            topic = self.get_topic(topic_arn)
            filtered = OrderedDict([(k, sub) for k, sub in self.subscriptions.items() if sub.topic == topic])
            return self._get_values_nexttoken(filtered, next_token)
        else:
            return self._get_values_nexttoken(self.subscriptions, next_token)

    def publish(self, topic_arn, message):
        topic = self.get_topic(topic_arn)
        message_id = topic.publish(message)
        return message_id

class Shard(object):
    def __init__(self, shard_id):
        self.shard_id = shard_id
        self.records = OrderedDict()

    def get_records(self, last_sequence_id, limit):
        last_sequence_id = int(last_sequence_id)
        results = []

        for sequence_number, record in self.records.items():
            if sequence_number > last_sequence_id:
                results.append(record)
                last_sequence_id = sequence_number

            if len(results) == limit:
                break

        return results, last_sequence_id

    def put_record(self, partition_key, data):
        # Note: this function is not safe for concurrency
        if self.records:
            last_sequence_number = self.get_max_sequence_number()
        else:
            last_sequence_number = 0
        sequence_number = last_sequence_number + 1
        self.records[sequence_number] = Record(partition_key, data, sequence_number)
        return sequence_number

    def get_min_sequence_number(self):
        if self.records:
            return list(self.records.keys())[0]
        return 0

    def get_max_sequence_number(self):
        if self.records:
            return list(self.records.keys())[-1]
        return 0

    def to_json(self):
        return {
            "HashKeyRange": {
                "EndingHashKey": "113427455640312821154458202477256070484",
                "StartingHashKey": "0"
            },
            "SequenceNumberRange": {
                "EndingSequenceNumber": self.get_max_sequence_number(),
                "StartingSequenceNumber": self.get_min_sequence_number(),
            },
            "ShardId": self.shard_id
        }

 def __init__(self, ec2_backend, region_name):
     self.region = region_name
     self.clusters = {}
     self.subnet_groups = {}
     self.security_groups = {
         "Default": SecurityGroup("Default", "Default Redshift Security Group", self.region)
     }
     self.parameter_groups = {
         "default.redshift-1.0": ParameterGroup(
             "default.redshift-1.0",
             "redshift-1.0",
             "Default Redshift parameter group",
             self.region
         )
     }
     self.ec2_backend = ec2_backend
     self.snapshots = OrderedDict()
     self.RESOURCE_TYPE_MAP = {
         'cluster': self.clusters,
         'parametergroup': self.parameter_groups,
         'securitygroup': self.security_groups,
         'snapshot': self.snapshots,
         'subnetgroup': self.subnet_groups
     }
     self.snapshot_copy_grants = {}

    def __init__(self,
                 name,
                 arn,
                 vpc_id,
                 protocol,
                 port,
                 healthcheck_protocol,
                 healthcheck_port,
                 healthcheck_path,
                 healthcheck_interval_seconds,
                 healthcheck_timeout_seconds,
                 healthy_threshold_count,
                 unhealthy_threshold_count):
        self.name = name
        self.arn = arn
        self.vpc_id = vpc_id
        self.protocol = protocol
        self.port = port
        self.healthcheck_protocol = healthcheck_protocol
        self.healthcheck_port = healthcheck_port
        self.healthcheck_path = healthcheck_path
        self.healthcheck_interval_seconds = healthcheck_interval_seconds
        self.healthcheck_timeout_seconds = healthcheck_timeout_seconds
        self.healthy_threshold_count = healthy_threshold_count
        self.unhealthy_threshold_count = unhealthy_threshold_count
        self.load_balancer_arns = []
        self.tags = {}

        self.attributes = {
            'deregistration_delay.timeout_seconds': 300,
            'stickiness.enabled': 'false',
        }

        self.targets = OrderedDict()

    def __init__(self, region, name, extended_config):
        self.region = region
        self.id = "{}_{}".format(self.region, str(uuid.uuid4().hex))
        self.name = name
        self.status = None
        self.extended_config = extended_config or {}
        self.creation_date = datetime.datetime.utcnow()
        self.last_modified_date = datetime.datetime.utcnow()

        self.clients = OrderedDict()
        self.identity_providers = OrderedDict()
        self.users = OrderedDict()
        self.refresh_tokens = {}
        self.access_tokens = {}
        self.id_tokens = {}

        with open(os.path.join(os.path.dirname(__file__), "resources/jwks-private.json")) as f:
            self.json_web_key = json.loads(f.read())

class DataPipelineBackend(BaseBackend):

    def __init__(self):
        self.pipelines = OrderedDict()

    def create_pipeline(self, name, unique_id, **kwargs):
        pipeline = Pipeline(name, unique_id, **kwargs)
        self.pipelines[pipeline.pipeline_id] = pipeline
        return pipeline

    def list_pipelines(self):
        return self.pipelines.values()

    def describe_pipelines(self, pipeline_ids):
        pipelines = [pipeline for pipeline in self.pipelines.values(
        ) if pipeline.pipeline_id in pipeline_ids]
        return pipelines

    def get_pipeline(self, pipeline_id):
        return self.pipelines[pipeline_id]

    def delete_pipeline(self, pipeline_id):
        self.pipelines.pop(pipeline_id, None)

    def put_pipeline_definition(self, pipeline_id, pipeline_objects):
        pipeline = self.get_pipeline(pipeline_id)
        pipeline.set_pipeline_objects(pipeline_objects)

    def get_pipeline_definition(self, pipeline_id):
        pipeline = self.get_pipeline(pipeline_id)
        return pipeline.objects

    def describe_objects(self, object_ids, pipeline_id):
        pipeline = self.get_pipeline(pipeline_id)
        pipeline_objects = [
            pipeline_object for pipeline_object in pipeline.objects
            if pipeline_object.object_id in object_ids
        ]
        return pipeline_objects

    def activate_pipeline(self, pipeline_id):
        pipeline = self.get_pipeline(pipeline_id)
        pipeline.activate()

class KinesisBackend(BaseBackend):

    def __init__(self):
        self.streams = OrderedDict()
        self.delivery_streams = {}

    def create_stream(self, stream_name, shard_count, region):
        if stream_name in self.streams:
            raise ResourceInUseError(stream_name)
        stream = Stream(stream_name, shard_count, region)
        self.streams[stream_name] = stream
        return stream

    def describe_stream(self, stream_name):
        if stream_name in self.streams:
            return self.streams[stream_name]
        else:
            raise StreamNotFoundError(stream_name)

    def list_streams(self):
        return self.streams.values()

    def delete_stream(self, stream_name):
        if stream_name in self.streams:
            return self.streams.pop(stream_name)
        raise StreamNotFoundError(stream_name)

    def get_shard_iterator(self, stream_name, shard_id, shard_iterator_type, starting_sequence_number,
                           at_timestamp):
        # Validate params
        stream = self.describe_stream(stream_name)
        shard = stream.get_shard(shard_id)

        shard_iterator = compose_new_shard_iterator(
            stream_name, shard, shard_iterator_type, starting_sequence_number, at_timestamp
        )
        return shard_iterator

    def get_records(self, shard_iterator, limit):
        decomposed = decompose_shard_iterator(shard_iterator)
        stream_name, shard_id, last_sequence_id = decomposed

        stream = self.describe_stream(stream_name)
        shard = stream.get_shard(shard_id)

        records, last_sequence_id, millis_behind_latest = shard.get_records(last_sequence_id, limit)

        next_shard_iterator = compose_shard_iterator(
            stream_name, shard, last_sequence_id)

        return next_shard_iterator, records, millis_behind_latest

    def put_record(self, stream_name, partition_key, explicit_hash_key, sequence_number_for_ordering, data):
        stream = self.describe_stream(stream_name)

        sequence_number, shard_id = stream.put_record(
            partition_key, explicit_hash_key, sequence_number_for_ordering, data
        )

        return sequence_number, shard_id

    def put_records(self, stream_name, records):
        stream = self.describe_stream(stream_name)

        response = {
            "FailedRecordCount": 0,
            "Records": []
        }

        for record in records:
            partition_key = record.get("PartitionKey")
            explicit_hash_key = record.get("ExplicitHashKey")
            data = record.get("Data")

            sequence_number, shard_id = stream.put_record(
                partition_key, explicit_hash_key, None, data
            )
            response['Records'].append({
                "SequenceNumber": sequence_number,
                "ShardId": shard_id
            })

        return response

    def split_shard(self, stream_name, shard_to_split, new_starting_hash_key):
        stream = self.describe_stream(stream_name)

        if shard_to_split not in stream.shards:
            raise ResourceNotFoundError(shard_to_split)

        if not re.match(r'0|([1-9]\d{0,38})', new_starting_hash_key):
            raise InvalidArgumentError(new_starting_hash_key)
        new_starting_hash_key = int(new_starting_hash_key)

        shard = stream.shards[shard_to_split]

        last_id = sorted(stream.shards.values(),
                         key=attrgetter('_shard_id'))[-1]._shard_id

        if shard.starting_hash < new_starting_hash_key < shard.ending_hash:
#.........这里部分代码省略.........

 def __init__(self):
     self.tables = OrderedDict()

class DynamoDBBackend(BaseBackend):

    def __init__(self):
        self.tables = OrderedDict()

    def create_table(self, name, **params):
        table = Table(name, **params)
        self.tables[name] = table
        return table

    def delete_table(self, name):
        return self.tables.pop(name, None)

    def update_table_throughput(self, name, throughput):
        table = self.tables[name]
        table.throughput = throughput
        return table

    def put_item(self, table_name, item_attrs):
        table = self.tables.get(table_name)
        if not table:
            return None
        return table.put_item(item_attrs)

    def get_table_keys_name(self, table_name):
        table = self.tables.get(table_name)
        if not table:
            return None, None
        else:
            return table.hash_key_attr, table.range_key_attr

    def get_keys_value(self, table, keys):
        if table.hash_key_attr not in keys or (table.has_range_key and table.range_key_attr not in keys):
            raise ValueError("Table has a range key, but no range key was passed into get_item")
        hash_key = DynamoType(keys[table.hash_key_attr])
        range_key = DynamoType(keys[table.range_key_attr]) if table.has_range_key else None
        return hash_key, range_key

    def get_table(self, table_name):
        return self.tables.get(table_name)

    def get_item(self, table_name, keys):
        table = self.get_table(table_name)
        if not table:
            return None
        hash_key, range_key = self.get_keys_value(table, keys)
        return table.get_item(hash_key, range_key)

    def query(self, table_name, hash_key_dict, range_comparison, range_value_dicts):
        table = self.tables.get(table_name)
        if not table:
            return None, None

        hash_key = DynamoType(hash_key_dict)
        range_values = [DynamoType(range_value) for range_value in range_value_dicts]

        return table.query(hash_key, range_comparison, range_values)

    def scan(self, table_name, filters):
        table = self.tables.get(table_name)
        if not table:
            return None, None, None

        scan_filters = {}
        for key, (comparison_operator, comparison_values) in filters.items():
            dynamo_types = [DynamoType(value) for value in comparison_values]
            scan_filters[key] = (comparison_operator, dynamo_types)

        return table.scan(scan_filters)

    def update_item(self, table_name, key, update_expression):
        table = self.get_table(table_name)

        hash_value = DynamoType(key)
        item = table.get_item(hash_value)
        item.update(update_expression)
        return item

    def delete_item(self, table_name, keys):
        table = self.tables.get(table_name)
        if not table:
            return None
        hash_key, range_key = self.get_keys_value(table, keys)
        return table.delete_item(hash_key, range_key)

 def __init__(self):
     self.stacks = OrderedDict()
     self.deleted_stacks = {}
     self.exports = OrderedDict()
     self.change_sets = OrderedDict()

class CloudFormationBackend(BaseBackend):

    def __init__(self):
        self.stacks = OrderedDict()
        self.deleted_stacks = {}
        self.exports = OrderedDict()
        self.change_sets = OrderedDict()

    def create_stack(self, name, template, parameters, region_name, notification_arns=None, tags=None, role_arn=None, create_change_set=False):
        stack_id = generate_stack_id(name)
        new_stack = FakeStack(
            stack_id=stack_id,
            name=name,
            template=template,
            parameters=parameters,
            region_name=region_name,
            notification_arns=notification_arns,
            tags=tags,
            role_arn=role_arn,
            cross_stack_resources=self.exports,
            create_change_set=create_change_set,
        )
        self.stacks[stack_id] = new_stack
        self._validate_export_uniqueness(new_stack)
        for export in new_stack.exports:
            self.exports[export.name] = export
        return new_stack

    def create_change_set(self, stack_name, change_set_name, template, parameters, region_name, change_set_type, notification_arns=None, tags=None, role_arn=None):
        if change_set_type == 'UPDATE':
            stacks = self.stacks.values()
            stack = None
            for s in stacks:
                if s.name == stack_name:
                    stack = s
            if stack is None:
                raise ValidationError(stack_name)

        else:
            stack = self.create_stack(stack_name, template, parameters,
                                      region_name, notification_arns, tags,
                                      role_arn, create_change_set=True)
        change_set_id = generate_changeset_id(change_set_name, region_name)
        self.stacks[change_set_name] = {'Id': change_set_id,
                                        'StackId': stack.stack_id}
        self.change_sets[change_set_id] = stack
        return change_set_id, stack.stack_id

    def execute_change_set(self, change_set_name, stack_name=None):
        stack = None
        if change_set_name in self.change_sets:
            # This means arn was passed in
            stack = self.change_sets[change_set_name]
        else:
            for cs in self.change_sets:
                if self.change_sets[cs].name == change_set_name:
                    stack = self.change_sets[cs]
        if stack is None:
            raise ValidationError(stack_name)
        if stack.events[-1].resource_status == 'REVIEW_IN_PROGRESS':
            stack._add_stack_event('CREATE_COMPLETE')
        else:
            stack._add_stack_event('UPDATE_IN_PROGRESS')
            stack._add_stack_event('UPDATE_COMPLETE')
        return True

    def describe_stacks(self, name_or_stack_id):
        stacks = self.stacks.values()
        if name_or_stack_id:
            for stack in stacks:
                if stack.name == name_or_stack_id or stack.stack_id == name_or_stack_id:
                    return [stack]
            if self.deleted_stacks:
                deleted_stacks = self.deleted_stacks.values()
                for stack in deleted_stacks:
                    if stack.stack_id == name_or_stack_id:
                        return [stack]
            raise ValidationError(name_or_stack_id)
        else:
            return list(stacks)

    def list_stacks(self):
        return self.stacks.values()

    def get_stack(self, name_or_stack_id):
        all_stacks = dict(self.deleted_stacks, **self.stacks)
        if name_or_stack_id in all_stacks:
            # Lookup by stack id - deleted stacks incldued
            return all_stacks[name_or_stack_id]
        else:
            # Lookup by stack name - undeleted stacks only
            for stack in self.stacks.values():
                if stack.name == name_or_stack_id:
                    return stack

    def update_stack(self, name, template, role_arn=None, parameters=None, tags=None):
        stack = self.get_stack(name)
        stack.update(template, role_arn, parameters=parameters, tags=tags)
        return stack

#.........这里部分代码省略.........

 def __init__(self, region_name=None):
     self.region_name = region_name
     self.tables = OrderedDict()

class DynamoDBBackend(BaseBackend):

    def __init__(self):
        self.tables = OrderedDict()

    def create_table(self, name, **params):
        if name in self.tables:
            return None
        table = Table(name, **params)
        self.tables[name] = table
        return table

    def delete_table(self, name):
        return self.tables.pop(name, None)

    def update_table_throughput(self, name, throughput):
        table = self.tables[name]
        table.throughput = throughput
        return table

    def update_table_global_indexes(self, name, global_index_updates):
        table = self.tables[name]
        gsis_by_name = dict((i['IndexName'], i) for i in table.global_indexes)
        for gsi_update in global_index_updates:
            gsi_to_create = gsi_update.get('Create')
            gsi_to_update = gsi_update.get('Update')
            gsi_to_delete = gsi_update.get('Delete')

            if gsi_to_delete:
                index_name = gsi_to_delete['IndexName']
                if index_name not in gsis_by_name:
                    raise ValueError('Global Secondary Index does not exist, but tried to delete: %s' %
                                     gsi_to_delete['IndexName'])

                del gsis_by_name[index_name]

            if gsi_to_update:
                index_name = gsi_to_update['IndexName']
                if index_name not in gsis_by_name:
                    raise ValueError('Global Secondary Index does not exist, but tried to update: %s' %
                                     gsi_to_update['IndexName'])
                gsis_by_name[index_name].update(gsi_to_update)

            if gsi_to_create:
                if gsi_to_create['IndexName'] in gsis_by_name:
                    raise ValueError('Global Secondary Index already exists: %s' % gsi_to_create['IndexName'])

                gsis_by_name[gsi_to_create['IndexName']] = gsi_to_create

        table.global_indexes = gsis_by_name.values()
        return table

    def put_item(self, table_name, item_attrs, expected=None, overwrite=False):
        table = self.tables.get(table_name)
        if not table:
            return None
        return table.put_item(item_attrs, expected, overwrite)

    def get_table_keys_name(self, table_name, keys):
        """
        Given a set of keys, extracts the key and range key
        """
        table = self.tables.get(table_name)
        if not table:
            return None, None
        else:
            if len(keys) == 1:
                for key in keys:
                    if key in table.hash_key_names:
                        return key, None
            # for potential_hash, potential_range in zip(table.hash_key_names, table.range_key_names):
            #     if set([potential_hash, potential_range]) == set(keys):
            #         return potential_hash, potential_range
            potential_hash, potential_range = None, None
            for key in set(keys):
                if key in table.hash_key_names:
                    potential_hash = key
                elif key in table.range_key_names:
                    potential_range = key
            return potential_hash, potential_range

    def get_keys_value(self, table, keys):
        if table.hash_key_attr not in keys or (table.has_range_key and table.range_key_attr not in keys):
            raise ValueError("Table has a range key, but no range key was passed into get_item")
        hash_key = DynamoType(keys[table.hash_key_attr])
        range_key = DynamoType(keys[table.range_key_attr]) if table.has_range_key else None
        return hash_key, range_key

    def get_table(self, table_name):
        return self.tables.get(table_name)

    def get_item(self, table_name, keys):
        table = self.get_table(table_name)
        if not table:
            raise ValueError("No table found")
        hash_key, range_key = self.get_keys_value(table, keys)
        return table.get_item(hash_key, range_key)

    def query(self, table_name, hash_key_dict, range_comparison, range_value_dicts,
              limit, exclusive_start_key, scan_index_forward, index_name=None, **filter_kwargs):
#.........这里部分代码省略.........

class Shard(BaseModel):

    def __init__(self, shard_id, starting_hash, ending_hash):
        self._shard_id = shard_id
        self.starting_hash = starting_hash
        self.ending_hash = ending_hash
        self.records = OrderedDict()

    @property
    def shard_id(self):
        return "shardId-{0}".format(str(self._shard_id).zfill(12))

    def get_records(self, last_sequence_id, limit):
        last_sequence_id = int(last_sequence_id)
        results = []
        secs_behind_latest = 0

        for sequence_number, record in self.records.items():
            if sequence_number > last_sequence_id:
                results.append(record)
                last_sequence_id = sequence_number

                very_last_record = self.records[next(reversed(self.records))]
                secs_behind_latest = very_last_record.created_at - record.created_at

            if len(results) == limit:
                break

        millis_behind_latest = int(secs_behind_latest * 1000)
        return results, last_sequence_id, millis_behind_latest

    def put_record(self, partition_key, data, explicit_hash_key):
        # Note: this function is not safe for concurrency
        if self.records:
            last_sequence_number = self.get_max_sequence_number()
        else:
            last_sequence_number = 0
        sequence_number = last_sequence_number + 1
        self.records[sequence_number] = Record(
            partition_key, data, sequence_number, explicit_hash_key)
        return sequence_number

    def get_min_sequence_number(self):
        if self.records:
            return list(self.records.keys())[0]
        return 0

    def get_max_sequence_number(self):
        if self.records:
            return list(self.records.keys())[-1]
        return 0

    def get_sequence_number_at(self, at_timestamp):
        if not self.records or at_timestamp < list(self.records.values())[0].created_at:
            return 0
        else:
            # find the last item in the list that was created before
            # at_timestamp
            r = next((r for r in reversed(self.records.values()) if r.created_at < at_timestamp), None)
            return r.sequence_number

    def to_json(self):
        return {
            "HashKeyRange": {
                "EndingHashKey": str(self.ending_hash),
                "StartingHashKey": str(self.starting_hash)
            },
            "SequenceNumberRange": {
                "EndingSequenceNumber": self.get_max_sequence_number(),
                "StartingSequenceNumber": self.get_min_sequence_number(),
            },
            "ShardId": self.shard_id
        }

class SNSBackend(BaseBackend):

    def __init__(self, region_name):
        super(SNSBackend, self).__init__()
        self.topics = OrderedDict()
        self.subscriptions = OrderedDict()
        self.applications = {}
        self.platform_endpoints = {}
        self.region_name = region_name
        self.sms_attributes = {}
        self.opt_out_numbers = ['+447420500600', '+447420505401', '+447632960543', '+447632960028', '+447700900149', '+447700900550', '+447700900545', '+447700900907']
        self.permissions = {}

    def reset(self):
        region_name = self.region_name
        self.__dict__ = {}
        self.__init__(region_name)

    def update_sms_attributes(self, attrs):
        self.sms_attributes.update(attrs)

    def create_topic(self, name):
        fails_constraints = not re.match(r'^[a-zA-Z0-9_-]{1,256}$', name)
        if fails_constraints:
            raise InvalidParameterValue("Topic names must be made up of only uppercase and lowercase ASCII letters, numbers, underscores, and hyphens, and must be between 1 and 256 characters long.")
        candidate_topic = Topic(name, self)
        if candidate_topic.arn in self.topics:
            return self.topics[candidate_topic.arn]
        else:
            self.topics[candidate_topic.arn] = candidate_topic
            return candidate_topic

    def _get_values_nexttoken(self, values_map, next_token=None):
        if next_token is None:
            next_token = 0
        next_token = int(next_token)
        values = list(values_map.values())[
            next_token: next_token + DEFAULT_PAGE_SIZE]
        if len(values) == DEFAULT_PAGE_SIZE:
            next_token = next_token + DEFAULT_PAGE_SIZE
        else:
            next_token = None
        return values, next_token

    def _get_topic_subscriptions(self, topic):
        return [sub for sub in self.subscriptions.values() if sub.topic == topic]

    def list_topics(self, next_token=None):
        return self._get_values_nexttoken(self.topics, next_token)

    def delete_topic(self, arn):
        topic = self.get_topic(arn)
        subscriptions = self._get_topic_subscriptions(topic)
        for sub in subscriptions:
            self.unsubscribe(sub.arn)
        self.topics.pop(arn)

    def get_topic(self, arn):
        try:
            return self.topics[arn]
        except KeyError:
            raise SNSNotFoundError("Topic with arn {0} not found".format(arn))

    def get_topic_from_phone_number(self, number):
        for subscription in self.subscriptions.values():
            if subscription.protocol == 'sms' and subscription.endpoint == number:
                return subscription.topic.arn
        raise SNSNotFoundError('Could not find valid subscription')

    def set_topic_attribute(self, topic_arn, attribute_name, attribute_value):
        topic = self.get_topic(topic_arn)
        setattr(topic, attribute_name, attribute_value)

    def subscribe(self, topic_arn, endpoint, protocol):
        # AWS doesn't create duplicates
        old_subscription = self._find_subscription(topic_arn, endpoint, protocol)
        if old_subscription:
            return old_subscription
        topic = self.get_topic(topic_arn)
        subscription = Subscription(topic, endpoint, protocol)
        self.subscriptions[subscription.arn] = subscription
        return subscription

    def _find_subscription(self, topic_arn, endpoint, protocol):
        for subscription in self.subscriptions.values():
            if subscription.topic.arn == topic_arn and subscription.endpoint == endpoint and subscription.protocol == protocol:
                return subscription
        return None

    def unsubscribe(self, subscription_arn):
        self.subscriptions.pop(subscription_arn)

    def list_subscriptions(self, topic_arn=None, next_token=None):
        if topic_arn:
            topic = self.get_topic(topic_arn)
            filtered = OrderedDict(
                [(sub.arn, sub) for sub in self._get_topic_subscriptions(topic)])
            return self._get_values_nexttoken(filtered, next_token)
        else:
            return self._get_values_nexttoken(self.subscriptions, next_token)
#.........这里部分代码省略.........