[Tutor] When was interned strings dropped (and why)?

[hcohen2]

As you have heard from me too many times: I am using ver. 2.2.2 and 
everytime I id the identical string it has a new location.

It was there in version 2.0.  Supposedly it had an advantage in 
performance, which should not be the primary reason for its inclusion.

What were its drawbacks, for it has obviously been dropped.

I am guessing, but doing a quick search it seems that making the 
formally built-in types objects that are subclassable sort of broken the 
single location for these base type objects.  When it is assigned to a 
variable (instance) it remains at that location.

Am I on the right track?