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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def callback(request):
 """Callback URL for Nexmo."""

    message_id = request.GET.get('messageId')
    status_id = request.GET.get('status')
    status_msg = NEXMO_STATUSES.get(status_id, UNKNOWN_STATUS)
    error_id = int(request.GET.get('err-code'))
    error_msg = NEXMO_MESSAGES.get(error_id, UNKNOWN_MESSAGE)

    logger.info(u'Nexmo callback: Sms = %s, Status = %s, message = %s' % (
        message_id,
        status_msg,
        error_msg
    ))

    # Nexmo expects a 200 response code
    return HttpResponse('')