def course_filename_prefix_generator(course_id, separator='_'):
 return get_valid_filename(unicode(separator).join([course_id.org, course_id.course, course_id.run]))

def course_filename_prefix_generator ( course_id , separator = '_' ) : return get_valid_filename ( unicode ( separator ) . join ( [ course_id . org , course_id . course , course_id . run ] ) )
generates a course-identifying unicode string for use in a file name .