docs: def locateChild(self, context, segments):
          """
          Delegate child lookup to the wrapped resource but wrap whatever results
          in another instance of this wrapper.
          """
          childDeferred = maybeDeferred(
              self.wrappedResource.locateChild, context, segments)
          def childLocated((resource, segments)):
              if (resource, segments) == NotFound:
                  return NotFound
              return _SecureWrapper(self.urlGenerator, resource), segments
          childDeferred.addCallback(childLocated)
          return childDeferred