@abc.abstractmethod<EOL><INDENT>def get_circle_of_trust(self, trust_id):<DEDENT>
return<EOL>
Gets a ``TrustList`` in the same circle, or the same level of confidence, as the given trust.

        In plenary mode, the returned list contains all known trusts or
        an error results. Otherwise, the returned list may contain only
        those trusts that are accessible through this session.

        :param trust_id: a trust ``Id``
        :type trust_id: ``osid.id.Id``
        :return: the returned ``Trust`` list
        :rtype: ``osid.authentication.process.TrustList``
        :raise: ``NotFound`` -- ``trust_id`` is not found
        :raise: ``NullArgument`` -- ``trust_id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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