Any other way to do it?
win32api?

Trying to run this in raspberry pi os (debian). But got the error as

server does not have extension for dpms option
xset:  unknown option force

Thanks for the script.
I encountered an issue using it in Windows 8.1.
It works fine, however; the script hangs even after I wake my monitors again.
e.g.
SC_MONITORPOWER = 0xF170
win32gui.SendMessage(win32con.HWND_BROADCAST, win32con.WM_SYSCOMMAND, SC_MONITORPOWER, 2)
print 'All done'

The Python window stays open even after I wake my monitors i.e. it never reaches the print 'All done' statement.

!/usr/bin/python

import subprocess
subprocess.call('echo "tell application "Finder" to sleep" | osascript ', shell=True)

This library is equivalent to unplugging the hdmi cable and then plugging it right back in.

So, it works for a brief few seconds [ appears to be shutoff ] until the computer finds the hdmi signal again, and the monitor continues as nothing happened.