invalid-envvar-value (PLE1507)

Derived from the Pylint linter.

What it does

Checks for os.getenv calls with an invalid key argument.

Why is this bad?

os.getenv only supports strings as the first argument (key).

If the provided argument is not a string, os.getenv will throw a TypeError at runtime.

Example

os.getenv(1)

Use instead:

os.getenv("1")