code: function create(modulePath, moduleStack) {
  
          // first check the cache to see if we already loaded it
          if (this.cache[modulePath]) {
              return this.cache[modulePath];
          }
  
          // try to get the resource for this module
          var resource;
          if (this.resources[modulePath]) {
              resource = this.resources[modulePath];
          }
          else if (this.resourceNames[modulePath]) {
              resource = this.injector.loadModule(this.resourceNames[modulePath] + 'Resource');
          }
          else {
              return null;
          }
  
          // get the service for this model
          var serviceName = modulePath.substring(0, 1).toLowerCase() + modulePath.substring(1) + 'Service';
          var service = this.injector.loadModule(serviceName, moduleStack);
  
          // save the model to cache and return it
          var Model = this.getModel(service, resource.mixins);
          this.cache[modulePath] = Model;
          return Model;
      }
docs: Create a model
  @param modulePath
  @param moduleStack