def render(request):
        """
        Render a request. This is called on the leaf resource for a request.

        @return: Either C{server.NOT_DONE_YET} to indicate an asynchronous or a
            C{bytes} instance to write as the response to the request.  If
            C{NOT_DONE_YET} is returned, at some point later (for example, in a
            Deferred callback) call C{request.write(b"<html>")} to write data to
            the request, and C{request.finish()} to send the data to the
            browser.

        @raise twisted.web.error.UnsupportedMethod: If the HTTP verb
            requested is not supported by this resource.
        """

        Render a request. This is called on the leaf resource for a request.

        @return: Either C{server.NOT_DONE_YET} to indicate an asynchronous or a
            C{bytes} instance to write as the response to the request.  If
            C{NOT_DONE_YET} is returned, at some point later (for example, in a
            Deferred callback) call C{request.write(b"<html>")} to write data to
            the request, and C{request.finish()} to send the data to the
            browser.

        @raise twisted.web.error.UnsupportedMethod: If the HTTP verb
            requested is not supported by this resource.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/resource.py