Python pretrained model file .plk try to open with matlab or convert .mat

I need to evaluate a matlab image according to a pre-trained model made in python. I have the .pkl .json and .model file. They would help me a lot since I have tried some codes and I get this

Code:

fid = py.open(filename,'rb');
data = py.pickle.load(fid);

Error:

Python Error: ValueError: embedded null character

I wish I could upload the file and if you can explain me if it is necessary only the .pkl file or why I need the other two files .json and .model

Thank you