In [pypa/keyring#445](https://github.com/pypa/keyring/445) and issue839151, we learned that there are Python interpreters in which `sys.argv` is an empty list, is not a list, or is not initialized at all. Through use of `sys.argv[0]`, the documentation strongly implies that `sys.argv` is always a list of at least one element. The documentation makes no mention of these other cases. It would be nice if the documentation would describe what values (or absence thereof) are valid for `sys.argv`.