code: def _descriptiveIdentifier(contactType):
      
      descriptiveIdentifierMethod = getattr(
          contactType, 'descriptiveIdentifier', None)
      if descriptiveIdentifierMethod is not None:
          return descriptiveIdentifierMethod()
      warn(
          "IContactType now has the 'descriptiveIdentifier'"
          " method, %s did not implement it" % (contactType.__class__,),
          category=PendingDeprecationWarning)
      return _objectToName(contactType).decode('ascii')
docs: Get a descriptive identifier for C{contactType}, taking into account the
      fact that it might not have implemented the C{descriptiveIdentifier}
      method.
  
      @type contactType: L{IContactType} provider.
  
      @rtype: C{unicode}