title: Error: 'tuple' object has no attribute 'shape'
body: <p>I have been writing a code about autoencoencoder for face recognition the part of code I used is as follows:</p>
  
  <pre><code>face_cascade = cv2.CascadeClassifier('C:/Users/PC/PycharmProjects/haarcascade_frontalface_default.xml')
  print(face_cascade)
  img = cv2.imread('C:/Users/PC/PycharmProjects/exmpforbike6/training_images/JenniferGroup.jpg')
  print(img)
  
  gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
  print("voici",gray)
  
  faces = face_cascade.detectMultiScale(gray, 1.3, 5)
  
  for (x, y, w, h) in faces:
      cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)
      roi_gray = gray[y:y + h, x:x + w]
      roi_color = img[y:y + h, x:x + w]
  
  a = []
  for i in range(0, faces.shape[0]):
      a.append(gray[faces[i][1]:faces[i][1] + faces[i][3], faces[i][0]:faces[i][0] + faces[i][2]])
  </code></pre>
  
  <p>this is the error i get :</p>
  
  <pre><code>AttributeError: 'tuple' object has no attribute 'shape'
  </code></pre>
  
  <p>the error is in this line:</p>
  
  <pre><code>for i in range(0, faces.shape[0]):
      a.append(gray[faces[i][1]:faces[i][1] + faces[i][3], faces[i][0]:faces[i][0] + faces[i][2]])
  </code></pre>
  
  <p>Any idea on how I can fix it??</p>