You could
Use a hotkey using the pykeyboard
library which you can read about at https://github.com/SavinaRoja/PyUserInput
or the keyboard
library at https://github.com/boppreh/keyboard
Another (but probably worse) option is:
You may use a "taskkill" command like
import os
os.system("taskkill /im chrome.exe /f")
However, this will just kill all processes and close the chosen program (in this case chrome.exe)
(This also may delete data from the browser, f.eks. you lose all you're windows even tho you have chosen in settings to save them for next time you open your browser)