code: def become(cls, session_token):
          
          response = client.get('/users/me', params={'session_token': session_token})
          content = response.json()
          user = cls()
          user._update_data(content)
          user._handle_save_result(True)
          if 'smsCode' not in content:
              user._attributes.pop('smsCode', None)
          return user
docs: 通过 session token 获取用户对象
  
          :param session_token: 用户的 session token
          :return: leancloud.User