Write a Python 3 program called pa1.py that implements a three-class linear classifier using the following method:

Training (using the training data set):
1. Compute the centroid of each class (e.g. A, B, and C).
2. Construct a discriminant function between each pair of classes (e.g. A/B, B/C, and A/C), halfway between the two centroids and orthogonal to the line connecting the two centroids. This is the basic linear classifier that we have discussed.