def was_active(reference_date_value, asset):
    """
    Whether or not `asset` was active at the time corresponding to
    `reference_date_value`.

    Parameters
    ----------
    reference_date_value : int
        Date, represented as nanoseconds since EPOCH, for which we want to know
        if `asset` was alive.  This is generally the result of accessing the
        `value` attribute of a pandas Timestamp.
    asset : Asset
        The asset object to check.

    Returns
    -------
    was_active : bool
        Whether or not the `asset` existed at the specified time.
    """
    return (asset.start_date.value <= reference_date_value <= asset.
        end_date.value)
