handleSubTypeAndParams -default value
diff --git a/js/base/Exchange.js b/js/base/Exchange.js
index 17f250d1f716..15dc503505bb 100644
--- a/js/base/Exchange.js
+++ b/js/base/Exchange.js
@@ -2143,7 +2143,7 @@ module.exports = class Exchange {
         return [ type, params ];
     }
 
-    handleSubTypeAndParams (methodName, market = undefined, params = {}) {
+    handleSubTypeAndParams (methodName, market = undefined, params = {}, defaultValue = 'linear') {
         let subType = undefined;
         // if set in params, it takes precedence
         const subTypeInParams = this.safeString2 (params, 'subType', 'defaultSubType');
@@ -2162,7 +2162,7 @@ module.exports = class Exchange {
             }
             // if it was not defined in market object
             if (subType === undefined) {
-                const values = this.handleOptionAndParams (undefined, methodName, 'subType', 'linear'); // no need to re-test params here
+                const values = this.handleOptionAndParams (undefined, methodName, 'subType', defaultValue); // no need to re-test params here
                 subType = values[0];
             }
         }
