/** 
 * @method
 * @desc Book#on - The method adds events that could be triggered by TC#trigger method
 * @param {string} names - Names of the events
 * @param {function} callback - Event handler
 * @param {boolean} [triggerOnInit] - If equals to true then event handler will be triggered immediately
 * @param {object} [context] - "this" context for the handler
 * @returns {object} - self
 * @example
 * //Returns this
 * this.on( 'change:x', function() {
 *   alert( 'x is changed' );
 * });
 * @example
 * //Returns this too. Alert will be execuded in window context and show secons argument, that has been passed to .trigger method ('Hello world')
 * this.on( 'ohmygosh', alert, window );
 * this.trigger( 'ohmygosh', 'Hello world' );
 * @example
 * //Shows "bar" alert immediately and waits for triggering "foo" event
 * this.on( 'foo', function() {
 *   alert( 'bar' );
 * }, true )
 * 
 */
function on(names, callback, triggerOnInit, context) {
  return 'blah';
}