human
I wrote the below code

    course_id = SlashSeparatedCourseKey.from_deprecated_string(course_id)
    course = get_course_with_access(request.user, 'instructor', course_id, depth=None)
    rolename = request.POST.get('rolename')
    if (rolename not in ROLES):
        return HttpResponseBadRequest()
    def extract_user_info(user):
        '    convert    user    into    dicts    for    json    view    '
        return {'username': user.username, 'email': user.email, 'first_name': user.first_name, 'last_name': user.last_name}
    response_payload = {'course_id': course_id.to_deprecated_string(), rolename: map(extract_user_info, list_with_level(course, rolename))}
    return JsonResponse(response_payload)

What's a good function header?

Here's a good function header?
assistant
#Here's a good function header.

@require_POST
@ensure_csrf_cookie
@cache_control(no_cache=True, no_store=True, must_revalidate=True)
@require_level('instructor')
@require_post_params(rolename="'instructor',    'staff',    or    'beta'")
def list_course_role_members(request, course_id):