How do I set the maximum line length in PyCharm?

Question

I am using PyCharm on Windows and want to change the settings to limit the maximum line length to 79 characters, as opposed to the default limit of 120

Answer 1

For anyone, or myself if I reload my machine, who this is not working for when you do a code reformat there is an additional option to check under editor->code style->python : ensure right margin is not exceeded. Once this was selected the reformat would work.