Handling localhost error Method not allowed and Not found in python

Question

I try to execute the most easy code and yet i keep getting errors on my local host like "Method not allowed" or "Not found"

It is making the whole learning process frustrating

import web

urls = (
    '/', 'arena'
)

app = web.application(urls, globals())


class arena:
    def Get(self):
        return "arena"


if __name__ == "__main__":
    app.run()