Gradient Descent Implementation in 3 core lines of Python

import matplotlib.pyplot as plt
import random
import numpy as np
from mpl_toolkits.mplot3d import Axes3D

x = np.array([np.array([1,j]) for j in range(5,)])
y = [j*j  for j in range(5,)]
p=np.ones(len(x[0]));

#We start here
for k in range(20000):
    for i,xi in enumerate(x):
        p = p - (0.001 * (((xi.dot(p)) - y[i]) * xi))/len(x)
#3 lines

print(p)