class_docstr: 通过该 callback 来测试模型的训练是否基本正常；
class_docstr_tok: ["\u901a\u8fc7\u8be5","callback","\u6765\u6d4b\u8bd5\u6a21\u578b\u7684\u8bad\u7ec3\u662f\u5426\u57fa\u672c\u6b63\u5e38\uff1b"]
code: def on_train_end(self, trainer):
      # assert self.loss < self.loss_begin_value
      if self.loss_threshold is not None:
          pass
  
imports: from fastNLP.core.callbacks.callback import Callback
label_desc: Use image node_id 3 for calling the RecordLossCallback obj's underlying member method code with example usage: obj.on_train_end(trainer) without return types