diff --git a/lib/index.js b/lib/index.js
index 8f30cc3a..b223917c 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -532,11 +532,15 @@ export function _checkPresentation(presentation) {
  *   VerifiableCredential.
  * @param {string|Date} [options.now] - A string representing date time in
  *   ISO 8601 format or an instance of Date. Defaults to current date time.
+ * @param {string} [options.mode] - The mode of operation for this
+ *   validation function, either `issue` or `verify`.
  *
  * @throws {Error}
  * @private
  */
-export function _checkCredential({credential, now = new Date(), mode = 'verify'}) {
+export function _checkCredential({
+  credential, now = new Date(), mode = 'verify'
+} = {}) {
   if(typeof now === 'string') {
     now = new Date(now);
   }