process = function(names, skip) {

                var i = 0, a = [], name, len, m, req, use;

                if (!names.length) {
                    return;
                }

                if (aliases) {
                    len = names.length;
                    for (i = 0; i < len; i++) {
                        if (aliases[names[i]] && !mods[names[i]]) {
                            a = [].concat(a, aliases[names[i]]);
                        } else {
                            a.push(names[i]);
                        }
                    }
                    names = a;
                }

                len = names.length;

                for (i = 0; i < len; i++) {
                    name = names[i];
                    if (!skip) {
                        r.push(name);
                    }

                    // only attach a module once
                    if (used[name]) {
                        continue;
                    }

                    m = mods[name];
                    req = null;
                    use = null;

                    if (m) {
                        used[name] = true;
                        req = m.details.requires;
                        use = m.details.use;
                    } else {
                        // CSS files don't register themselves, see if it has
                        // been loaded
                        if (!G_ENV._loaded[VERSION][name]) {
                            missing.push(name);
                        } else {
                            used[name] = true; // probably css
                        }
                    }

                    // make sure requirements are attached
                    if (req && req.length) {
                        process(req);
                    }

                    // make sure we grab the submodule dependencies too
                    if (use && use.length) {
                        process(use, 1);
                    }
                }

            }
Called from the `use` method queue to ensure that only one set of loading
    logic is performed at a time.

    @method _use
    @param {String} args* One or more modules to attach.
    @param {Function} [callback] Function to call once all required modules have
        been attached.
    @private