diff --git a/src/core/2.base.js b/src/core/2.base.js
index dc94a3d98..ba7bc06b2 100644
--- a/src/core/2.base.js
+++ b/src/core/2.base.js
@@ -640,15 +640,15 @@
             var result = [];
             var used = [];
             for (var b in object) {
-                if (this.has(object, b)) {
-                    if (!this.isEqual(object[b], other[b])) {
+                if (BI.has(object, b)) {
+                    if (!BI.isEqual(object[b], other[b])) {
                         result.push(b);
                     }
                     used.push(b);
                 }
             }
             for (var b in other) {
-                if (this.has(other, b) && !BI.contains(used, b)) {
+                if (BI.has(other, b) && !BI.contains(used, b)) {
                     result.push(b);
                 }
             }