def __init__(self, network, parentRegion = None, ontologyTerm = None, *args, **keywords):
     """
     Regions represent a physical subset of a nervous system.  They can also be hierarchical with regions nested within other regions.  Regions can also be associated with an entry in one of the :class:`ontologies <Library.Ontology.Ontology>` in the library.
     
     You create a region by messaging a network:
     
     >>> region1 = network.createRegion(...)
     """
     
     if ontologyTerm is not None:
         if 'name' not in keywords:
             keywords['name'] = ontologyTerm.name
         if 'abbreviation' not in keywords and ontologyTerm.abbreviation is not None:
             keywords['abbreviation'] = ontologyTerm.abbreviation
     
     NeuroObject.__init__(self, network, *args, **keywords)
     
     self.parentRegion = None
     self.subRegions = []
     self.ontologyTerm = ontologyTerm
     self.arborizations = []
     self.pathways = []
     self.neurons = []
     if parentRegion is not None:
         parentRegion._addSubRegion(self)