def needs_change(destination, dependencies):
    last_dependency_change = 0
    for dependency in dependencies:
        if dependency is None:
            return False
        last_dependency_change = max(
            last_dependency_change, 
            dependency.lstat().st_mtime
        )

    if not destination.exists():
        return True

    return destination.lstat().st_mtime < last_dependency_change