gae_function_urls.py

URLS=[]
def create_url(url, method='get'):
    def wrapper(func):
        cls = type(func.func_name + 'Handler', (BaseHandler,), {method.lower():func})
        URLS.append((url, cls))
        def inner(*args, **kwargs):
            return func(*args, **kwargs)
        return inner
    return wrapper

... Your Functions...

app = webapp2.WSGIApplication(URLS, debug=os.environ['SERVER_SOFTWARE'].startswith('Dev'))
"""
Usage:
@create_url(<path>, [<get or post>])
def function(self):
  ... YOUR CODE ...
"""