from typing import Optional


def validate_cyclic_lifetime(cyclic_lifetime: Optional[int]) -> Optional[int]:
    """
    Validates the cyclic lifetime of an object.
    Cyclic lifetime is always optional.

    :param cyclic_lifetime: The cyclic_lifetime of the object.
    :return: The validated cyclic lifetime.
    """
    if cyclic_lifetime is None:
        return None

    if cyclic_lifetime <= 0:
        raise ValueError("Cyclic lifetime must be positive.")

    return cyclic_lifetime