def is_enrolled_by_partial(cls, user, course_id_partial):
        """
        Returns `True` if the user is enrolled in a course that starts with
        `course_id_partial`. Otherwise, returns False.

        Can be used to determine whether a student is enrolled in a course
        whose run name is unknown.

        `user` is a Django User object. If it hasn't been saved yet (no `.id`
               attribute), this method will automatically save it before
               adding an enrollment for it.

        `course_id_partial` (CourseKey) is missing the run component
        """
        assert isinstance(course_id_partial, CourseKey)
        assert not course_id_partial.run  # None or empty string
        course_key = SlashSeparatedCourseKey(course_id_partial.org, course_id_partial.course, '')
        querystring = unicode(course_key.to_deprecated_string())
        try:
            return CourseEnrollment.objects.filter(
                user=user,
                course_id__startswith=querystring,
                is_active=1
            ).exists()
        except cls.DoesNotExist:
            return False