def get_family_hierarchy_session(self):
if not self.supports_family_hierarchy():<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.FamilyHierarchySession(proxy=self._proxy,<EOL>runtime=self._runtime)<EOL><DEDENT>except AttributeError:<EOL><INDENT>raise OperationFailed()<EOL><DEDENT>return session<EOL>
Gets the ``OsidSession`` associated with the family hierarchy service.

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