docs: def badRequestMethod(self, environ, start_response):
          """
          Return HTTP 400 Bad Request.
          """
          response = "400 Bad Request\n\nTo access this PyAMF gateway you " \
              "must use POST requests (%s received)" % environ['REQUEST_METHOD']
  
          start_response('400 Bad Request', [
              ('Content-Type', 'text/plain'),
              ('Content-Length', str(len(response))),
              ('Server', gateway.SERVER_NAME),
          ])
  
          return [response]