def addBoth(self, callback, *args, **kw):
        """
        Convenience method for adding a single callable as both a callback
        and an errback.

        See L{addCallbacks}.
        """
        return self.addCallbacks(callback, callback,
                                 callbackArgs=args, errbackArgs=args,
                                 callbackKeywords=kw, errbackKeywords=kw)

        Convenience method for adding a single callable as both a callback
        and an errback.

        See L{addCallbacks}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/defer.py