Python2 script to convert coloured image to grayscale

color2grayscale.py

import cv2 as cv

def convert(filename):
	img = cv.imread(filename)
	gray = cv.cvtColor(img, cv.COLOR_RGB2GRAY)
	return cv.imwrite(filename, gray)

if __name__ == '__main__':
	filename = raw_input('filename: ')
	if filename:
            print('status: ' + str(convert(filename)))