/** @type {Object} */
var history;

var _ = {
    once: function(fn) {},
    difference: function(a, b) {},
    union: function(a) {}
};

/**
 * @param {string} name
 * @param {Array.<string>} deps
 * @param {Function} factory
 * @return {*}
 */
var define = function(name, deps, factory) {};

/** @type {boolean} */
define.amd = false;

/** @type {Object} */
var module;

/**
 * @param {string} name
 * @return {*}
 */
var require = function(name) {};