def get_referrer_from_request(request):
    # determine what source led the user to the export directory
    # if navigating internally then return None
    return 'aaa'

def get_referrer_from_request(request):
    # TODO: determine what source led the user to the export directory
    # if navigating internally then return None (ticket ED-138)
    return 'aaa'

Add TODO to comment in registration helper to reduce risk of task being forgotten
Add TODO to comment in registration helper to reduce risk of task being forgotten
