Nested labels in Gmail

The quick search did not bring articles on its wings with references to the appearance of this beautiful feature in Gmail (which is strange). However, it is something that I personally have long lacked. Namely, the ability to make nested labels and, accordingly, filter letters with the assignment of these labels.
I always wondered why they didn’t do it, and here it is - hanging in the labs. And the article on Google about this feature is dated as much as Thursday, April 08, 2010.

The brief English content is:
For example, if you want to do so, you can use the following text: Home , Home / Kids and Home / Shopping. "

UPD : on the sensible recommendation of spmbt , I add a short Russian version (slightly corrected):
If you think this may be useful for you, go to the "Gmail Labs" tab in the "Settings" section, look at the "Attached Labels", turn it on and click the "Save" button. After that you need to name your label with a slash (/), to make it a descendant of another label. For example, suppose you wanted to create a simple hierarchy of "Home" shortcuts, with nested "Family" and "Vacations". In this case, simply create labels with the following names:
House
Home / Family
House / Vacation
')
In general ... one of the coolest additions to the gmail, in my humble opinion.

PS: I tried to create (from the filter) label / foo label when there was already label-foo, said that label / foo already exists. Removed label-foo - it was created normally.

PPS: people around you say the feature has been seen before and it’s me so unenlightened. Tell me pliz if so - I will stub out of sight as an unnecessary evidence of personal vital backwardness.