今天刚装了个TensorFlow2.4，import tensorflow的时候，出现如下错误
TypeError: Descriptors cannot not be created directly.
If this call came from a _pb2.py file, your generated code is out of date and must be regenerated with protoc >= 3.19.0.
If you cannot immediately regenerate your protos, some other possible workarounds are:
1. Downgrade the protobuf package to 3.20.x or lower.
2. Set PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python (but this will use pure-Python parsing and will be much slower).
这是由于我们用pip安装tensorflow的时候，安装依赖包protobuf的版本过高造成的。
卸掉原来的，在重新装一个指定版本的就行了。
pip uninstall protobuf
pip install protobuf==3.19.0
