Additionally, you can ensure that a string is interned by explicitly calling the intern() builtin.

>>> s = 'sesquipedalian'
>>> t = 'sesqui' + 'pedalian'
>>> s is t
False
>>> t = intern('sesqui' + 'pedalian')
>>> s is t
True

It strikes me as odd that no-one in that thread mentioned intern(), as far as I saw.