RuntimeError: Python 3.5 or later is required

After creating a virtual environment (python=3.4.5) using conda, the package cannot be installed using pip, and the error message is as follows:

RuntimeError: Python 3.5 or later is required

After investigation, the cause of the final lock error is: the pip version is inconsistent with the python version (the specific reason is unknown, because pip is automatically installed).
Solution:

1、
	卸载pip
2、
	conda install "pip<19.2" python=3.4
3、
	更新pip版本
	pip install --upgrade pip==**.**.**