import cv2 as cvimport numpy as npdef watershed(img):    gray = cv.cvtColor(img, cv.COLOR_RGB2GRAY)    ret, binary = cv.threshold(gray, 0, 255, cv.THRESH_BINARY | cv.THRESH_OTSU)    kernel = cv.getStructuringElement(cv.MORPH_RECT, (3, 3))    mb = cv.morphologyEx(binary, cv.MORPH_OPEN, kernel, iterations=2)    sure_bg = cv.dilate(mb, kernel, iterations=3)    dist = cv.distanceTransform(mb, cv.DIST_L2, 3)    dist_output = cv.normalize(dist, 0, 1.0, cv.NORM_MINMAX)    ret, surface = cv.threshold(dist, dist.max() * 0.6, 255, cv.THRESH_BINARY)    surface_fg = np.uint8(surface)    unknown = cv.subtract(sure_bg, surface_fg)    ref, markers = cv.connectedComponents(sure_bg)    markers = markers + 1    markers[unknown == 255] = 0    markers = cv.watershed(src, markers=markers)    src[markers == -1] = [0, 0, 255]    cv.imshow("result",src)src = cv.imread('num.jpg')cv.imshow('def', src)watershed(src)cv.waitKey(0)cv.destroyAllWindows()