@utilities.arguments_not_none<EOL><INDENT>def can_update_grades(self, grade_system_id):<DEDENT>
raise errors.Unimplemented()<EOL>
Tests if this user can update ``Grades``.

        A return of true does not guarantee successful authorization. A
        return of false indicates that it is known updating a ``Grade``
        will result in a ``PermissionDenied``. This is intended as a
        hint to an application that may not wish to offer update
        operations to unauthorized users.

        arg:    grade_system_id (osid.id.Id): the ``Id`` of a
                ``GradeSystem``
        return: (boolean) - ``false`` if ``Grade`` modification is not
                authorized, ``true`` otherwise
        raise:  NullArgument - ``grade_system_id`` is ``null``
        *compliance: mandatory -- This method must be implemented.*