var com = com || {};
com.igt = com.igt || {};

com.igt.extern = function(namespace) {
    'use strict';
    var o, n, lastname, names;

    namespace = (namespace || '').split('.');
    lastname = namespace.pop();

    for (o = this; n = namespace.shift(); o = o[n]) {
        o[n] = o[n] || {};
    }
    if (o[lastname]) {
        console.warn(namespace + ' is already declared');
    }
    o[lastname] = void 0;
}