def data() -> str:
    """
    Test data for day_01.

    Returns
    -------
    data: str
    """
    data = (
        'abc\n'
        '\n'
        'a\nb\nc\n'
        '\n'
        'ab\nac\n'
        '\n'
        'a\na\na\na\n'
        '\n'
        'b'
        )
    return data