Usage of mutable value in function signature of connect

[skewty]

Observed behavior

Mutable values in function signatures are bad form in python and should be avoided.

This potential code issue is picked up by most linters. Perhaps Ruff should be leveraged by this project to help catch these issues?

Expected behavior

async def connect(servers: Union[str, List[str]] = ""], **options) -> NATS:
    nc = NATS()
    await nc.connect(servers or "nats://localhost:4222", **options)
    return nc

Server and client version

nats.py/nats/__init__.py

Line 21 in 9310e6f

servers: Union[str, List[str]] = ["nats://localhost:4222"],

Host environment

No response

Steps to reproduce

No response

[caspervonb]

Started moving over to GitHub Actions so we can turn on linting and formatting inline here #568

[charles-dyfis-net]

If this were changed from List[str] to Sequence[str], then one could use a tuple: ("nats://localhost:4222",)