code: function(name, options) {
          debug('.getGenerator', name);
  
          if (name === 'this') {
            return this;
          }
  
          var gen = this.findGenerator(name, options);
          if (utils.isValidInstance(gen)) {
            return gen.invoke(gen, options);
          }
        }
docs: Get generator `name` from `app.generators`, same as [findGenerator], but also invokes
  the returned generator with the current instance. Dot-notation may be used for getting
  sub-generators.
  
  ```js
  var foo = app.getGenerator('foo');
  
  // get a sub-generator
  var baz = app.getGenerator('foo.bar.baz');
  ```
  @name .getGenerator
  @param {String} `name` Generator name.
  @return {Object|undefined} Returns the generator instance or undefined.
  @api public