A python implementation of business process drift detection method Detecting drift from event streams of unpredictable business processes
P.S. I don't know how to implement G-Test algorithm, so I used Chi-Squared Test instead. The result shows that Chi-Squared Test works well too. The original papaer has no interest to me. I just used this algorithm in my graduation thesis and found it's a very solid work, so I posted a python implementation and hope this may help you.