Count the number of pixel values in the image

import cv2
import numpy as np

image = cv2.imread("./train_label/image100.png")
classes_nums        = np.zeros([256], np.float32)
classes_nums += np.bincount(np.reshape(label, [-1]), minlength=256)

print(" Print the value and number of pixels .")
print('-' * 37)
print("| %15s | %15s |"%("Key", "Value"))
print('-' * 37)
for i in range(256):
    if classes_nums[i] > 0:
        print("| %15s | %15s |"%(str(i), str(classes_nums[i])))
        print('-' * 37)