open cv 3.0, findContours return "too many value to unpack"

edit

yes, that seems to have changed in 3.0.

import cv2

help(cv2.findContours)

Help on built-in function findContours in module cv2:

findContours(...)

findContours(image, mode, method[, contours[, hierarchy[, offset]]]) -> image, contours, hierarchy

so, you probably need:

_, contours, hierarchy = cv2.findContours(...)

(one more return value)