def init_feature(name):
    chunks = name.split('-')
    if chunks[0] == 'sift':
        detector = cv2.SIFT()
        norm = cv2.NORM_L2
    elif chunks[0] == 'surf':
        detector = cv2.SURF(800)
        norm = cv2.NORM_L2
    elif chunks[0] == 'orb':
        detector = cv2.ORB(400)
        norm = cv2.NORM_HAMMING
    else:
        return None, None
    if chunks in 'flann':
        if norm == cv2.NORM_L2:
            flann_params = dict(algorithm = FLANN_INDEX_KDTREE, trees = 5)
        else:
            flann_params= dict(algorithm = FLANN_INDEX_LSH,
                               table_number = 6, # 12
                               key_size = 12,     # 20
                               multi_probe_level = 1) #2
        matcher = cv2.FlannBasedMatcher(flann_params, {})  # bug : need to pass empty dict (#1329)
    else:
        matcher = cv2.BFMatcher(norm)
    return detector, matcher
dataset/ETHPy150Open fatcloud/PyCV-time/opencv-official-samples/2.4.9/find_obj.py/init_feature/swapped operands of `in`