docs: add asyncio in multi-agent-applications.md to make examples can be run "as is".

[ME-Msc]

Examples cannot be run "as is" without asyncio.

[samuelcolvin]

you'll need to use single quotes.

Best to run tests before committing which will pick this up, if you run uv run pytest --update-examples, it'll even fix them for you.

[samuelcolvin]

As I said before

Best to run tests before committing which will pick this up, if you run uv run pytest --update-examples, it'll even fix them for you.

[ME-Msc]

As I said before

Best to run tests before committing which will pick this up, if you run uv run pytest --update-examples, it'll even fix them for you.

Thanks for your reply. I tried it and meet a failure. Could you help me with that? I have no idea.

[samuelcolvin]

😞 looks like a bug in pytest-examples we can't ignore, I'll try to fix it.

[ME-Msc]

Ok, thank you. I will wait for it. I will create an issue about it.

[ME-Msc]

#632 Have created an issue.

[samuelcolvin]

Okay, I see what's going on here, the problem is caused by calling main twice: once with asyncio.run(main()) and once via the call argument here:

pydantic-ai/tests/test_examples.py

Line 122 in 06eac85

module_dict = eval_example.run_print_update(example, call=call_name)

Honestly I would rather keep the examples short and omit

if __name__ == '__main__':
    asyncio.run(main())

I think it's pretty obvious to most developers that you'll need to call main via asyncio.run(main()). Happy to accept a PR to add

_(This example is complete, it can be run "as is" — you'll need to add `asyncio.run(main())` to run `main`)_

to all examples that need it.

[ME-Msc]

Thank you for your help!

A new PR #638 has been created.

And I suggest to add uv run pytest --update-examples in docs/contributing.md, helping newcomers like me to make contributions.