def put_async(self, newtext,
                  comment=None, watchArticle=None, minorEdit=True, force=False,
                  callback=None):
(...) 
        callback: a callable object that will be called after the page put
                  operation; this object must take two arguments:
                  (1) a Page object, and (2) an exception instance, which
                  will be None if the page was saved successfully.