productivity shocks for Pep 1-t model

Hi!

I am a beginner in CGE and I am making my own adaptation of the Pep 1-t model (https://www.pep-net.org/research-resources/cge-models). The model does not seem to have any productivity growth in it, so I would like to add it, both to the baseline and to shocks. Does anyone have examples of something similar or suggestions how I could get ideas?