title: AttributeError: 'Sequential' object has no attribute 'predict_classes'/
body: <p>Whenever I try run this code, it displays:</p>
  <pre><code> AttributeError: 'Sequential' object has no attribute 'predict_classes'
  </code></pre>
  <p>The first line returns the error:</p>
  <pre><code>result = str(model.predict_classes(roi, 1, verbose = 0)[0])
  cv2.putText(copy, getLetter(result), (300 , 100), cv2.FONT_HERSHEY_COMPLEX, 2, (0, 255, 0), 2)
  cv2.imshow('frame', copy)    
  </code></pre>