Using maker for new elements

[a-k-holod]

In documentation there is a paragraph:

Create your own elements
In this example, we will add a Google Maps element.

With the Maker Bundle, you can create a new UiElement very easily:

> bin/console make:ui-element

Then you will have to answer some questions, or you can add arguments to the command to avoid the questions.

> bin/console make:ui-element app.google_maps "map pin"

Just add the translations!

But running that returns:

                                             
bin/console make:ui-element

                                             
  Command "make:ui-element" is not defined.  
                                             

 Do you want to run "make:grid" instead?  (yes/no) [no]:

Is that feature outdated or not implemented yet?