'Returns a list containing the top level XModuleDescriptors of the courses in this modulestore.'

@strip_key
def get_courses(self, **kwargs):

    courses = {}
    for store in self.modulestores:
        for course in store.get_courses(**kwargs):
            course_id = self._clean_locator_for_mapping(course.id)
            if (course_id not in courses):
                courses[course_id] = course
    return courses.values()
