def get_build_datetime() -> datetime:
    """
    Returns an aware datetime object.

    Support SOURCE_DATE_EPOCH environment variable for reproducible builds.
    See https://reproducible-builds.org/specs/source-date-epoch/
    """
    source_date_epoch = os.environ.get('SOURCE_DATE_EPOCH')
    if source_date_epoch is None:
        return datetime.now(timezone.utc)

    return datetime.fromtimestamp(int(source_date_epoch), timezone.utc)

    Returns an aware datetime object.

    Support SOURCE_DATE_EPOCH environment variable for reproducible builds.
    See https://reproducible-builds.org/specs/source-date-epoch/
    
mkdocs/utils/__init__.py