wtf?

import sys
sys.path.append('/usr/local/lib/python2.7/site-packages')

import numpy as np
import cv2

# Capture video from camera
# cap = cv2.VideoCapture(0)

# Capture video from file
cap = cv2.VideoCapture('road.mp4')
number_cascade = cv2.CascadeClassifier("haarcascade_russian_plate_number.xml")

while(cap.isOpened()):
    # Capture frame-by-frame
    ret, frame = cap.read()
    print 'ret = %d\n'%ret

    # Our operations on the frame come here
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    numbers = number_cascade.detectMultiScale(gray, 1.01, 3 ,minSize=(10, 10), flags=cv2.cv.CV_HAAR_SCALE_IMAGE)
    if numbers != ():
        for (x,y,w,h) in numbers:
            cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
            # roi_gray = gray[y:y+h, x:x+w]
            roi_color = frame[y:y+h, x:x+w]

    # Display the resulting frame
    cv2.imshow('frame', gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()