def getChildWithDefault(self, path, request):
        """
        Inspect the Authorization HTTP header, and return a deferred which,
        when fired after successful authentication, will return an authorized
        C{Avatar}. On authentication failure, an C{UnauthorizedResource} will
        be returned, essentially halting further dispatch on the wrapped
        resource and all children
        """
        # Don't consume any segments of the request - this class should be
        # transparent!
        request.postpath.insert(0, request.prepath.pop())
        return self._authorizedResource(request)

        Inspect the Authorization HTTP header, and return a deferred which,
        when fired after successful authentication, will return an authorized
        C{Avatar}. On authentication failure, an C{UnauthorizedResource} will
        be returned, essentially halting further dispatch on the wrapped
        resource and all children
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/_auth/wrapper.py