Capture Video and make Grayscale using OpenCV Python

import cv2
import numpy as np

cap = cv2.VideoCapture(0)

while True:
    ret, frame = cap.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    cv2.imshow("gray", gray)

    # exit video capture
    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

cap.release()
cv2.destroyAllWindows()

References
https://www.youtube.com/watch?v=Jvf5y21ZqtQ
https://github.com/mhdr/OpenCV/tree/master/002