def get_relationship_family_session(self):
if not self.supports_relationship_family():<EOL><INDENT>raise Unimplemented()<EOL><DEDENT>try:<EOL><INDENT>from . import sessions<EOL><DEDENT>except ImportError:<EOL><INDENT>raise OperationFailed()<EOL><DEDENT>try:<EOL><INDENT>session = sessions.RelationshipFamilySession(proxy=self._proxy,<EOL>runtime=self._runtime)<EOL><DEDENT>except AttributeError:<EOL><INDENT>raise OperationFailed()<EOL><DEDENT>return session<EOL>
Gets the ``OsidSession`` to lookup relationship/family mappings.

        return: (osid.relationship.RelationshipFamilySession) - a
                ``RelationshipFamilySession``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_relationship_family()`` is
                ``false``
        *compliance: optional -- This method must be implemented if ``supports_relationship_family()`` is ``true``.*