(self, data)
return None
return next state, or None if not handled.
return next state, or None if not handled.
return next state or None if not handled .
def process(self, data):
        """return next state, or None if not handled."""
        if self.match(data):
            return self.handle(data)
        return None
def process ( self , data ) : if self . match ( data ) : return self . handle ( data ) return None