code: def _sign_response(self, response):
          
          if 'Authorization' not in request.headers:
              return response
  
          try:
              mohawk_receiver = mohawk.Receiver(
                  credentials_map=self._client_key_loader_func,
                  request_header=request.headers['Authorization'],
                  url=request.url,
                  method=request.method,
                  content=request.get_data(),
                  content_type=request.mimetype,
                  accept_untrusted_content=current_app.config['HAWK_ACCEPT_UNTRUSTED_CONTENT'],
                  localtime_offset_in_seconds=current_app.config['HAWK_LOCALTIME_OFFSET_IN_SECONDS'],
                  timestamp_skew_in_seconds=current_app.config['HAWK_TIMESTAMP_SKEW_IN_SECONDS']
              )
          except mohawk.exc.HawkFail:
              return response
  
          response.headers['Server-Authorization'] = mohawk_receiver.respond(
              content=response.data,
              content_type=response.mimetype
          )
          return response
docs: Signs a response if it's possible.