I know. But try it in a PythonAnywhere console and you'll see it doesn't work. booking.com are blocking the request somehow. I just don't think you're going to be able to get it to work on PythonAnywhere in the same way as it does on your PC.
So your choices are either to try and find an API to get reviews from booking.com, or to try another host. I suppose you could also try to use some sort of VPN...
Ultimately, though, as Glenn says, it looks like booking.com don't want people to scrape their website in that way -- you'll probably find it's against their Terms and Conditions. And, really, we can't help you to break other site's Ts & Cs...