stream.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

   async with session.get_screen_streamer(want_contents=True) as streamer:
       while True:
           content = await streamer.async_get()
           for i in range(content.number_of_lines):
               line = content.line(i)
               print(line.string)


iterm2.run_until_complete(main)