AttributeError: module 'models' has no attribute 'MichaelisMentenModel'

[chloea31]

I contact you because I have a problem when I try to execute the notebook 00_Choosing a Process Model.ipynb: in cell 3, the attribute does not seem to be recognized.

In the python script models.py that I cloned, on the branch master, the class MichaelisMentenModel() is not defined. Did I miss something? Would there be other files? How can I solve this problem?