Compare two `Info` objects to see if they should be copied.

    Returns:
        bool: `True` if the `Info` are different in size or mtime.

def _compare(info1, info2):
    # type: (Info, Info) -> bool
    """Compare two `Info` objects to see if they should be copied.

    Returns:
        bool: `True` if the `Info` are different in size or mtime.

    """
    # Check filesize has changed
    if info1.size != info2.size:
        return True
    # Check modified dates
    date1 = info1.modified
    date2 = info2.modified
    return date1 is None or date2 is None or date1 > date2