def _retrieve_course(course_key):
 course = modulestore().get_course(course_key, depth=0)
 if (course is None):
  raise CourseNotFoundError
 return course

def _retrieve_course ( course_key ) : course = modulestore ( ) . get_course ( course_key , depth = 0 ) if ( course is None ) : raise CourseNotFoundError return course
retrieves the course for the given course key .