When Python 2 installs tensorflow, test after the installation is completed:

import tensorflow as tf

Will report an error:

Traceback (most recent call last):
File “<stdin>”, line 1, in <module>
File “/home/zhaokai/.local/lib/python2.7/site-packages/tensorflow/__init__.py”, line 28, in <module>
from tensorflow.python import pywrap_tensorflow  # pylint: disable=unused-import
File “/home/zhaokai/.local/lib/python2.7/site-packages/tensorflow/python/__init__.py”, line 52, in <module>
from tensorflow.core.framework.graph_pb2 import *
File “/home/zhaokai/.local/lib/python2.7/site-packages/tensorflow/core/framework/graph_pb2.py”, line 7, in <module>
from google.protobuf import descriptor as _descriptor
File “/home/zhaokai/.local/lib/python2.7/site-packages/google/protobuf/descriptor.py”, line 113
class DescriptorBase(metaclass=DescriptorMetaclass):
^
SyntaxError: invalid syntax

The solution is to re-install protobuf:

pip install protobuf==3.17.3

then Import tensorflow again.