Add types + Make library PEP-561 compatible #528

Why

I love types, and want everything in python typed as strongly as possible within reason. This creates more readable code and makes refactoring easier and safer. If i debug my code that depend on ably code, i find myself stepping into untyped ably code, this makes it harder to read.

The following import triggers an mypy error

game\utils\event_publisher.py

from ably import AblyRest

Running mypy .

game\utils\event_publisher.py:6: error: Skipping analyzing "ably": module is installed, but missing library stubs or py.typed marker  [import]
game\utils\event_publisher.py:6: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

In addition i see the very prominent Channel.publish is not typed.

My suggestions are

• Make your library PEP-561 compatible
• Type all public exposed code
• Add mypy or other type checking to your CI/CD pipelines
• If possible type the whole repo

Read more here

• https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
• https://mypy.readthedocs.io/en/stable/installed_packages.html#installed-packages
• https://peps.python.org/pep-0561/

┆Issue is synchronized with this Jira Task by Unito