Example is not working #3

Hello, Conan!
Just clone pyreact to try it, but instead of the clock I saw ¨click the clock for a new random color¨.
In which direction should I see to debug it? (I did try it on RaspberryPi if it matter https://www.raspberrypi.org/)
Additions:

Uncaught Error: Clock(...): Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.
at invariant (react-dom-16.0.0.js:65)
at reconcileChildFibers (react-dom-16.0.0.js:10539)
at reconcileChildrenAtPriority (react-dom-16.0.0.js:11198)
at reconcileChildren (react-dom-16.0.0.js:11189)
at finishClassComponent (react-dom-16.0.0.js:11325)
at mountIndeterminateComponent (react-dom-16.0.0.js:11486)
at beginWork (react-dom-16.0.0.js:11672)
at performUnitOfWork (react-dom-16.0.0.js:13644)
at workLoop (react-dom-16.0.0.js:13753)
at HTMLUnknownElement.callCallback (react-dom-16.0.0.js:1527)

react-dom-16.0.0.js:72