Fun machine learning stuff
model.py contains a neural network made with NumPy that can be used for classification.
example.py builds a neural network of the class NN, described in model.py, and trains it on the Iris dataset to distinguish the type "versicolor" from the other types, based on the attributes petal length and petal width.
P.S. This is not an attempt to reinvent the wheel, since neural nets are efficiently implemented in frameworks like TF, but rather to review the mathematical background behind it :)