Support Python 3.5.2 (Xenial)?

[jacobperron]

Feature request

Feature description

Until recently, launch was compatible with Python 3.5.2, which is the current default version for python3 on Ubuntu Xenial, but now is broken.

#167, introduced the following line:

launch/launch/launch/actions/opaque_coroutine.py

Line 20 in d5ace50

from typing import Coroutine

Coroutine is not available in the typing module until Python 3.5.3 (reference).

I think it's an easy fix as we can use something like TypeVar('Coroutine') as a replacement.
But, I'm not sure if we plan to support Xenial in Dashing and/or if we'd like to keep launch backwards compatible (given that it's an easy fix).

[dirk-thomas]

Duplicate of ros2/build_farmer#170.

[jacobperron]

Duplicate of ros2/build_farmer#170.

@dirk-thomas Okay. What do you think about #196 as an alternate solution? I've been using it locally as I'm running Xenial. But I don't mind upgrading to Bionic if we're dropping support for Xenial.

[jacobperron]

I've seen your comment in #196 👍