AppEngine get/post on webapp2.RequestHandler
Yes, you can easily alias one method to another:

class Save(webapp2.RequestHandler):

    def post(self):
        #...

    get = post


But although I don't know anything about your application, you shouldn't alias GET to POST like this: the two methods have different semantics. GET is a safe method — it must only retrieve data and not update or store it — while POST is an unsafe method — it requests the server to store or update the data in the request. See "Safe methods" in Wikipedia.