import cv2
import numpy as np;

params = cv2.SimpleBlobDetector_Params()

ver = (cv2.__version__).split('.')
if int(ver[0]) < 3 :
    detector = cv2.SimpleBlobDetector(params)
else : 
    detector = cv2.SimpleBlobDetector_create(params)

detector.empty() # <- now works
keypoints = detector.detect(image) # <- now works