Tox envlist using any python3 interpreter, exactly once

In my tox.ini

file I have

[tox]
envlist = py27,py33,py34
skip_missing_interpreters = True

      

        
        
        
      

    

but i'm really trying to test one python3

and not very interested in versions of the smaller one python3

. I am just trying to maintain the environments in which it is installed python-3.3

, but not python-3.4

and vice versa. This is inconvenient because

• the list of intepreters will grow endlessly
• when multiple interpreters are available (my laptop has both 3.3 and 3.4) the tests are run multiple times and it takes time

Ideally there would be a way to write:

[tox]
envlist = py27,py3

      

        
        
        
      

    

to select any version of python3. I don't think this is possible, but maybe there is a workaround?