@abc.abstractmethod<EOL><INDENT>def get_functions_by_genus_type(self, function_genus_type):<DEDENT>
return<EOL>
Gets a ``FunctionList`` corresponding to the given function genus ``Type`` which does not include functions of genus types derived from the specified ``Type``.

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

        :param function_genus_type: a function genus type
        :type function_genus_type: ``osid.type.Type``
        :return: the returned ``Function`` list
        :rtype: ``osid.authorization.FunctionList``
        :raise: ``NullArgument`` -- ``function_genus_type`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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