@classmethod
def from_protobuf(cls, pb):
    """
        Get an instance of this class based on the protobug representation from the Datastore API.

        :type pb: :class:`gcloudoem.datastore.datastore_v1_pb2.Entity`
        :param pb: The protobuf representing the entity.

        :return: Instance of cls.
        """
    raise NotImplementedError
