from typing import Optional


def _parse_result(potfile_line: str) -> Optional[str]:
    """Helper function which parses a single .potfile line and returns the password part.

    Hashcat uses its .potfile format to report results. In this format, each line consists of the
    hash and its matching word, separated with a colon (e.g. `asdf1234:password`).
    """
    if potfile_line:
        return potfile_line.split(":")[-1].strip()
    return None