The polymode manual suggests that creating new polymodes should be very easy:
Creating new polymodes typically takes a few lines of code.
I wanted to set it up to make emacs to switch to python mode inside of
pythontex commands and environments. For the object oriented approach seems to be more complex to modify than just adding some delimiters to a list in my .emacs file. So I don't even see how to start and where to save apply my modifications.
So how would the equivalent setup for polymode look like as that given by JeanPierre for mmm-mode: https://emacs.stackexchange.com/a/20150/2323