addLoadPromisesFromPkgs = function (pkgs) {
            for (var i = 0, il = pkgs.length; i < il; i++) {
              var pkgForPromises = pkgs[i];
              var pkgForPromisesId = pkgForPromises.getId();
              if (pkgForPromises !== pkg && loadPromisesForResourcesSeenById[pkgForPromisesId] == null) {
                loadPromisesForResourcesSeenById[pkgForPromisesId] = true;
                loadPromisesForResources.push(pkgForPromises.getPromise());
              }
            }
          }
Loads all resources in a package that are not required by any other package and returns a promise. Will attempt to automatically load all resources defined by PKGS.getPkgForIdentifier(id).
@param {String|Number|Integer} id package id
@param {Array} [resources=null] list of resources not included in the package defined by PKGS.getPkgForIdentifier(id)
@param {Function} [progressHandler] function to be called on progress where first argument is progress between 0 and 1
@param {Boolean} [preventAllocation] whether loaded assets will be prevented from being allocated
@returns {Promise}
@example
PackageManager.getInstance().loadPackage(
 "packageId",
 ["path1", "path2", ..., "pathN"],
 function (percentLoaded) {
   // handle progress
   // progress is not supported by promises
   // so to handle progress you must pass in a function as the third parameter
 }
).then(function () {
 // handle completion
 // completion handlers must be registered using promise methods such as "then"
});