-        [
-            {source: extension.document, target: doc},
-            {source: extension.documentNode, target: [doc.ElementNodeFactory.prototype, doc.TextNodeFactory.prototype]},
-
-        ].forEach(function(mapping) {
-            if(mapping.source) {
-                if(mapping.source.methods) {
-                    existingPropertyNames = _.values(mapping.target)
-                    _.pairs(mapping.source.methods).forEach(function(pair) {
-                        var methodName = pair[0],
-                            method = pair[1],
-                            targets = _.isArray(mapping.target) ? mapping.target : [mapping.target];
-                        if(_.contains(existingPropertyNames, methodName)) {
-                            throw new Error('Cannot extend {target} with method name {methodName}. Name already exists.'
-                                .replace('{target}', mapping.target)
-                                .replace('{methodName}', methodName)
-                            );
-                        }
-                        targets.forEach(function(target) {
-                            target[methodName] = method;
-                        });
-                    });
-                }
+    registerClassMethod: function(methodName, method, className) {
+        var thisClassMethods = (this.classMethods[className] = this.classMethods[className] || {});
+        thisClassMethods[methodName] = method;
+    },