code: function _findType(details, keys) {
    if (details.card != null) {
      return keys.indexOf("card");
    } else if (details.bank_account != null) {
      return keys.indexOf("bank_account");
    } else if (details.pii != null) {
      return keys.indexOf("pii");
    } else return false;
  }
docs: Stripe normally only allows for fetch format for the details provided. _findType allows the user to use the node format of the details by figuring out which format/type the details provided are.