title: TypeError: The added layer must be an instance of class Layer. Found: <keras.engine.input_layer.InputLayer object at 0x7fc6f1b92240>
body: <p>I am trying to add vgg16 layers to Sequential model but getting the error mentioned in the Question Title </p>
  
  <pre><code>from keras.applications.vgg16 import VGG16
  
  from tensorflow.contrib.keras.api.keras.models import Sequential
  vgg_model = VGG16()
  model = Sequential()
  #print(model.summary())
  for layer in vgg_model.layers:
          model.add(layer)
  
  print(model.summary())
  </code></pre>
  
  <p>I am using keras 2.2.4       </p>
  
  <pre><code>TypeError: The added layer must be an instance of class Layer. Found: &lt;keras.engine.input_layer.InputLayer object at 0x7fc6f1b92240&gt;
  </code></pre>