whole_func_string: function() {
          var me = this,
              copy = new this.self(me.initialConfig);
  
          copy.add(me.keys, me.items);
          return copy;
      }
func_code_string: function() {
          var me = this,
              copy = new this.self(me.initialConfig);
  
          copy.add(me.keys, me.items);
          return copy;
      }
func_documentation_string: Creates a shallow copy of this collection
  @return {Ext.util.MixedCollection}
  @since Ext 1