def _make_publisher(catalog_or_dataset):
    """De estar presentes las claves necesarias, genera el diccionario
    "publisher" a nivel catálogo o dataset."""
    level = catalog_or_dataset
    keys = [k for k in ["publisher_name", "publisher_mbox"] if k in level]
    if keys:
        level["publisher"] = {
            key.replace("publisher_", ""): level.pop(key) for key in keys
        }
    return level