How to convert images from one color-space to another (BGR, HSV)

Syntax for color coversion cv2.cvtColor(img, conversion_type) img: Any input image conversion_type: COLOR_BGR2GRAY, COLOR_BGR2HSV etc. How to convert BGR to Gray? cv2.cvtColor(img, COLOR_BGR2GRAY) How to convert BGR to HSV? cv2.cvtColor(img, COLOR_BGR2HSV)