iTerm2 Python API: how to run a command AND capture result

Question

It's quite easy to send a command using the API:

#!/usr/bin/env python3

import tkinter as tk
import iterm2
# To install, update, or remove packages from PyPI, use Scripts > Manage > Manage Dependencies...

async def main(connection):
    # Your code goes here. Here's a bit of example code that adds a tab to the current window:
    app = await iterm2.async_get_app(connection)
    session = app.current_window.current_tab.current_session
    if session is not None:
        await session.async_send_text('date\n')     

But how to capture the result of this command? I've checked:

• ScreenStreamer
• async_get_contents

(see API doc)

But nothing is really working for me. Any thoughts?