'Returns whether the user has staff access to the course
associated with this CourseUsageInfo instance.
For performance reasons (minimizing multiple SQL calls), the
value is cached within this instance.'

@property
def has_staff_access(self):

    if (self._has_staff_access is None):
        self._has_staff_access = _has_access_to_course(self.user, 'staff', self.course_key)
    return self._has_staff_access
