OpenCV Python (Image Masking using Inpaint Function) Please help!!

I am using Python IDLE to edit and run script...

I need help with modifying the following inprint.py program, so when a user press 'r' the program
masks the image and produces output which is the image in black and white and only the masked area
is in color...

#!/usr/bin/env python

'''
Inpainting sample.

Inpainting repairs damage to images by floodfilling
the damage with surrounding image areas.

Usage:
inpaint.py [<image>]

Keys:
SPACE - inpaint
r     - reset the inpainting mask
ESC   - exit
'''

import numpy as np
import cv2
from common import Sketcher

if __name__ == '__main__':
    import sys
    try: fn = sys.argv[1]
    except: fn = '../cpp/fruits.jpg'
    print __doc__

    img = cv2.imread(fn)
    img_mark = img.copy()
    mark = np.zeros(img.shape[:2], np.uint8)
    sketch = Sketcher('img', [img_mark, mark], lambda : ((255, 255, 255), 255))

    while True:
        ch = 0xFF & cv2.waitKey()
        if ch == 27:
            break
        if ch == ord(' '):
            res = cv2.inpaint(img_mark, mark, 3, cv2.INPAINT_TELEA)
            cv2.imshow('inpaint', res)
        if ch == ord('r'):
            img_mark[:] = img
            mark[:] = 0
            sketch.show()
    cv2.destroyAllWindows()