def process_args(self, frame, anchor, args, kwargs):
     if len(args) == 1:
         frame.raise_expt(ErrorConfig.MaybeKeyNotFound())
     return BuiltinConstMethod.process_args(self, frame, anchor, args,
                                            kwargs)
 def get_element(self, frame, anchor, key, write=False):
     if write:
         key.connect(self.key.recv)
     else:
         frame.raise_expt(ErrorConfig.MaybeKeyNotFound())
     return self.value