Update lib/schema.js

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: vkarpov15

lib/schema.js

@@ -692,10 +692,13 @@ Schema.prototype._defaultToObjectOptions = function(json) {
  * @param {'csfle' | 'queryableEncryption' | undefined} encryptionType plain object with paths to add, or another schema
  */
 Schema.prototype.encryptionType = function encryptionType(encryptionType) {
+  if (arguments.length === 0) {
+    return this.options.encryptionType;
+  }
   if (typeof encryptionType === 'string' || encryptionType === null) {
     this.options.encryptionType = encryptionType;
   } else {
-    return this.options.encryptionType;
+    throw new TypeError('Invalid encryptionType. Expected a string, null, or no arguments.');
   }
 };