Load cache from the disk.

    Return:
        set: Deserialized data from disk.

def load_cache():
    """
    Load cache from the disk.

    Return:
        set: Deserialized data from disk.
    """
    if not os.path.exists(settings.DUP_FILTER_FILE):
        return set()

    with open(settings.DUP_FILTER_FILE) as f:
        return set(
            json.loads(f.read())
        )