def get_url(pif, dataset, version=1, site="https://citrination.com"):
    """
    Construct the URL of a PIF on a site
    :param pif: to construct URL for
    :param dataset: the pif will belong to
    :param version: of the PIF (default: 1)
    :param site: for the dataset (default: https://citrination.com)
    :return: the URL as a string
    """
    return "{site}/datasets/{dataset}/version/{version}/pif/{uid}".format(
        uid=pif.uid, version=version, dataset=dataset, site=site
    )