def add_member(self, userprofile, status=GroupMembership.MEMBER):
        """
        Add a user to this group. Optionally specify status other than member.

        If user is already in the group with the given status, this is a no-op.

        If user is already in the group with a different status, their status will
        be updated.
        """
        defaults = dict(status=status, date_joined=now())
        membership, created = GroupMembership.objects.get_or_create(
            userprofile=userprofile, group=self, defaults=defaults
        )
        if created:
            if status == GroupMembership.MEMBER:
                # Joined
                update_basket_task.delay(userprofile.id)
        elif not created and membership.status != status:
            # Status changed
            old_status = membership.status
            membership.status = status
            membership.save()
            update_basket_task.delay(userprofile.id)
            if (old_status, status) == (GroupMembership.PENDING, GroupMembership.MEMBER):
                # Request accepted
                email_membership_change.delay(self.pk, userprofile.user.pk, old_status, status)

    def add_member(self, userprofile, status=GroupMembership.MEMBER):
        """
        Add a user to this group. Optionally specify status other than member.

        If user is already in the group with the given status, this is a no-op.

        If user is already in the group with a different status, their status will
        be updated if the change is a promotion. Otherwise, their status will not change.
        """
        defaults = dict(status=status,
                        date_joined=now())
        membership, created = GroupMembership.objects.get_or_create(userprofile=userprofile,
                                                                    group=self,
                                                                    defaults=defaults)
        if created:
            if status == GroupMembership.MEMBER:
                # Joined
                # Group is functional area, we want to sent this update to Basket
                if self.functional_area:
                    update_basket_task.delay(userprofile.id)
        else:
            if membership.status != status:
                # Status changed
                old_status = membership.status
                membership.status = status
                if (old_status, status) == (GroupMembership.PENDING, GroupMembership.MEMBER):
                    # Request accepted
                    membership.save()
                    if self.functional_area:
                        # Group is functional area, we want to sent this update to Basket.
                        update_basket_task.delay(userprofile.id)
                    email_membership_change.delay(self.pk, userprofile.user.pk, old_status, status)

 def remove_member(self, userprofile, send_email=True):
     membership = GroupMembership.objects.get(group=self, userprofile=userprofile)
     old_status = membership.status
     membership.delete()
     update_basket_task.delay(userprofile.id)
     if old_status == GroupMembership.PENDING and send_email:
         # Request denied
         email_membership_change.delay(self.pk, userprofile.user.pk, old_status, None)

def toggle_group_subscription(request, url):
    """Toggle the current user's membership of a group."""
    group = get_object_or_404(Group, url=url)
    profile = request.user.userprofile

    # We don't operate on system groups using this view.
    if not group.system:
        if profile.groups.filter(id=group.id).exists():
            profile.groups.remove(group)
        else:
            profile.groups.add(group)
        update_basket_task.delay(profile.id)

    return redirect(reverse('groups:show_group', args=[group.url]))

    def remove_member(self, userprofile, send_email=True):
        try:
            membership = GroupMembership.objects.get(group=self, userprofile=userprofile)
        except GroupMembership.DoesNotExist:
            return
        old_status = membership.status
        membership.delete()

        # If group is functional area, we want to sent this update to Basket
        if self.functional_area:
            update_basket_task.delay(userprofile.id)

        if old_status == GroupMembership.PENDING and send_email:
            # Request denied
            email_membership_change.delay(self.pk, userprofile.user.pk,
                                          old_status, None)

    def add_member(self, userprofile, status=GroupMembership.MEMBER):
        """
        Add a user to this group. Optionally specify status other than member.

        If user is already in the group with the given status, this is a no-op.

        If user is already in the group with a different status, their status will
        be updated if the change is a promotion. Otherwise, their status will not change.

        If the group in question is the NDA group, also add the user to the NDA newsletter.
        """
        defaults = dict(status=status, date_joined=now())
        membership, created = GroupMembership.objects.get_or_create(userprofile=userprofile,
                                                                    group=self,
                                                                    defaults=defaults)
        if membership.status != status:
            # Status changed
            # The only valid status change states are:
            # PENDING to MEMBER
            # PENDING to PENDING_TERMS
            # PENDING_TERMS to MEMBER

            old_status = membership.status
            membership.status = status
            statuses = [(GroupMembership.PENDING, GroupMembership.MEMBER),
                        (GroupMembership.PENDING, GroupMembership.PENDING_TERMS),
                        (GroupMembership.PENDING_TERMS, GroupMembership.MEMBER)]
            if (old_status, status) in statuses:
                # Status changed
                membership.save()
                if membership.status in [GroupMembership.PENDING, GroupMembership.MEMBER]:
                    email_membership_change.delay(self.pk, userprofile.user.pk, old_status, status)
                # Since there is no demotion, we can check if the new status is MEMBER and
                # subscribe the user to the NDA newsletter if the group is NDA
                if self.name == settings.NDA_GROUP and status == GroupMembership.MEMBER:
                    update_basket_task.delay(userprofile.id, [settings.BASKET_NDA_NEWSLETTER])

def update_basket(sender, instance, **kwargs):
    update_basket_task.delay(instance.id)

def update_basket(sender, instance, **kwargs):
    if instance.is_vouched:
        update_basket_task.delay(instance.id)
    elif instance.basket_token:
        unsubscribe_from_basket_task.delay(instance.email, instance.basket_token)

def update_basket(sender, instance, **kwargs):
    newsletters = [settings.BASKET_VOUCHED_NEWSLETTER]
    if instance.is_vouched:
        update_basket_task.delay(instance.id, newsletters)
    elif instance.basket_token:
        unsubscribe_from_basket_task.delay(instance.email, instance.basket_token, newsletters)