print_screen.py

#!/usr/bin/env python3.7

import iterm2

async def main(connection):
   app = await iterm2.async_get_app(connection)
   session = app.current_terminal_window.current_tab.current_session

   contents = await session.async_get_screen_contents()
   for i in range(contents.number_of_lines):
       line = contents.line(i)
       print(line.string)

iterm2.run_until_complete(main)