wtrite python code to implement color2gray

Sure, here's a Python code to implement color2gray:

import cv2

# Load the color image
img = cv2.imread('color_image.jpg')

# Convert the image to grayscale
gray_img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

# Save the grayscale image
cv2.imwrite('gray_image.jpg', gray_img)

This code uses the OpenCV library to load a color image, convert it to grayscale, and save the grayscale image. Note that you'll need to replace 'color_image.jpg' with the filename of your own color image.