@abc.abstractmethod<EOL><INDENT>def get_authority(self):<DEDENT>
return<EOL>
Gets the authority of this ``Type``.

        The authority is a string used to ensure the uniqueness of this
        ``Type`` when using a non- federated identifier space.
        Generally, it is a domain name identifying the party responsible
        for this ``Type``. This method is used to compare one ``Type``
        to another.

        :return: the authority of this ``Type``
        :rtype: ``string``


        *compliance: mandatory -- This method must be implemented.*