Please excuse me for asking what I am sure is a newbie question. 
Searching the pkgsrc documentation has not brought me an answer to this 
question.

On my tiny NetBSD test system I have somehow ended up with two Pythons
python21-pth and python22. I have built all of my packages from source 
using pkgsrc, but somewhere along the line an extra python got 
installed.

I would like to get to having just one installed, python22-pth (An app 
I am hoping to use needs the pthread capability)

Is there a 'best' way to replace the python21-pth with python22-pth and 
delete the python22 (non-pth)

I am running pkgsrc-current and I have a number of dependencies on 
python21-pth, but only three on the python22.

What I am thinking is that I can probably afford to delete the (newer) 
python22 and its 3 dependencies and then upgrade the python21-pth to 
python22-pth and reinstall the apps I need somehow making sure that 
they see the installed python (somehow they missed the first time which 
is how I ended up where I am).

Whats the best sequence of commands for pkgsrc to use to do this that 
ensures the desired results? Is there a reference to consult on issues 
like this besides the pkgsrc documentation, which doesn't go into 
length on what to do in case of package conflicts like this, as far as 
I can tell.

Nick
(learning as I go along)