NameError: name 'np' is not defined in logistic_regr.py

[cllei12]

Thank you for your wonderful repo! I am learning how to use your Logistic Model Trees, but I find an error in the impelement of Logistic Regression.

In dvanced_ML/model_tree/models/logistic_regr.py, the functionlogistic_regr.prediction() is trying to call np.ones(), but package numpy didn't be imported inlogistic_regr.py. It seems we should add import numpy as np in this script.

[ShubhamZoro]

I would like to add numpy to the file.