def human_delta(duration):
    """Converts seconds into a human-readable delta"""
    delta = []
    if duration // (60**2 * 24 * 365) > 0:
        delta.append(f"{duration // (60**2 * 24 * 365)} years")
        duration %= 60**2 * 24 * 365
    if duration // (60**2 * 24 * 30) > 0:
        delta.append(f"{duration // (60**2 * 24 * 30)} months")
        duration %= 60**2 * 24 * 30
    if duration // (60**2 * 24) > 0:
        delta.append(f"{duration // (60**2 * 24)} days")
        duration %= 60**2 * 24
    if duration // 60**2 > 0:
        delta.append(f"{duration // 60**2} hours")
        duration %= 60**2
    if duration // 60 > 0:
        delta.append(f"{duration // 60} minutes")
        duration %= 60
    if duration > 0:
        delta.append(f"{duration} seconds")
    if len(delta) == 0:
        delta = ["Forever"]
    return ", ".join(delta)