def get_function_search_session_for_vault(self, vault_id=None):
if vault_id is None:<EOL><INDENT>raise NullArgument<EOL><DEDENT>raise Unimplemented()<EOL>
Gets the ``OsidSession`` associated with the function search service for the given vault.

        arg:    vault_id (osid.id.Id): the ``Id`` of the vault
        return: (osid.authorization.FunctionSearchSession) - a
                ``FunctionSearchSession``
        raise:  NotFound - ``vault_id`` not found
        raise:  NullArgument - ``vault_id`` is ``null``
        raise:  OperationFailed - ``unable to complete request``
        raise:  Unimplemented - ``supports_function_search()`` or
                ``supports_visible_federation()`` is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_function_search()`` and
        ``supports_visible_federation()`` are ``true``.*