Python 3.5 pip 9 AttributeError: 'NoneType' object has no attribute 'bytes'

You can try this following:

python -m pip install -U --force-reinstall pip

My answer is a variation of assmmahmud's but for me I had to use the option --user. I'm on windows so from CMD.exe;

py -m pip install --user --force-reinstall -U

If I don't use the --user option then the error occurs.

Try using easy_install -U pip, according to this bug report.

Edit: Okay, go to "https://pypi.org/simple/pip/", and download the latest .whl file (scroll to the bottom). When you have it, open cmd in the same folder (by clicking File -> open powershell/cmd in the file explorer), and type

pip install filename, with filename being the name of the file you downloaded (Should be pip-18.0-py2.py3-none-any.whl).

Try that and tell me if it works.