code: def route_not_found(*args):
          
          response_data = jsonify(ServiceErrorResponses._MISSING_AUTHENTICATION)
          return make_response(response_data, ServiceErrorResponses.HTTP_STATUS_CODE_403)
docs: Constructs a Flask Response for when a API Route (path+method) is not found. This is usually
          HTTP 404 but with API Gateway this is a HTTP 403 (https://forums.aws.amazon.com/thread.jspa?threadID=2166840)
  
          :return: a Flask Response