code: def wait(self, method, *args):
          
          methodargs = encode_args(args, extra=True)
          js = """
          %s(%s wait_callback);
          """ % (method, methodargs)
          self._send(js)
docs: Call a method on the zombie.js Browser instance and wait on a callback.
  
          :param method: the method to call, e.g., html()
          :param args: one of more arguments for the method