#Three lines to make our compiler able to draw: import sys import matplotlib matplotlib.use('Agg') import numpy as np import matplotlib.pyplot as plt from scipy.cluster.hierarchy import dendrogram, linkage x = [4, 5, 10, 4, 3, 11, 14 , 6, 10, 12] y = [21, 19, 24, 17, 16, 25, 24, 22, 21, 21] data = list(zip(x, y)) linkage_data = linkage(data, method='ward', metric='euclidean') dendrogram(linkage_data) plt.show() #Two lines to make our compiler able to draw: plt.savefig(sys.stdout.buffer) sys.stdout.flush()