[Python] pip install selenium fails and reports raise ReadTimeoutError(self._pool, None, “Read timed out.”)

Problem: When using pip install selenium directly, the error
is reported as follows:
raise ReadTimeoutError(self._pool, None, “Read timed out.”)

Solution: Use pip3 install selenium -i https://pypi.douban.com/simple/ --trusted-host pypi.douban.com
to succeed