code: def map(cls, value):
          
  
          if cls._map is None:
              raise ValueError(unwrap(
                  '''
                  %s._map has not been defined
                  ''',
                  type_name(cls)
              ))
  
          if not isinstance(value, str_cls):
              raise TypeError(unwrap(
                  '''
                  value must be a unicode string, not %s
                  ''',
                  type_name(value)
              ))
  
          return cls._map.get(value, value)
docs: Converts a dotted unicode string OID into a mapped unicode string
  
          :param value:
              A dotted unicode string OID
  
          :raises:
              ValueError - when no _map dict has been defined on the class
              TypeError - when value is not a unicode string
  
          :return:
              A mapped unicode string