问题：
OSError: Error no file named pytorch_model.bin, tf_model.h5, model.ckpt.index or flax_model.msgpack found in directory
出现过程：
使用transformers的Bertmodel时
问题代码：
model = Bertmodel.from_pretrained('bert_model')问题原因：
下载的模型文件夹中没有pytorch_model.bin/tf_model.h5等文件，去原网址中查找也未发现相关文件。继而查看transformers官方使用说明：
from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
pretrained_model_name_or_path – either: - a string with the shortcut name of a pre-trained model to load from cache or download, e.g.: bert-base-uncased. - a string with the identifier name of a pre-trained model that was user-uploaded to our S3, e.g.: dbmdz/bert-base-g