code: function(type, listener){
          if (typeof this._handlers[type] == "undefined"){
              this._handlers[type] = [];
          }
  
          this._handlers[type].push(listener);
      }
docs: ------------------------------------------------------------------------- Event Handling ------------------------------------------------------------------------- 
  Adds a listener for a given event type.
  @param {String} type The type of event to add a listener for.
  @param {Function} listener The function to call when the event occurs.
  @return {void}
  @method attach