from typing import Dict


def extract_commit_message_metadata(message: str) -> Dict[str, str]:
    """Extract extended metadata stored in the Git commit message.

    For example, a commit that looks like this::

        Do the thing!

        Piper-Changelog: 1234567

    Will return::

        {"Piper-Changelog": "1234567"}

    """
    metadata = {}
    for line in message.splitlines():
        if ":" not in line:
            continue

        key, value = line.split(":", 1)
        metadata[key] = value.strip()

    return metadata