title: How to pass multiple inputs in Keras?
body: <p>I would like to compare images with custom model. So, I have model with 2 inputs. </p>
  
  <p>How to feed two inputs for train and validation?</p>
  
  <p>If I do</p>
  
  <pre><code>self.classifier.fit([x1_train, x2_train], y_train,
                                  batch_size=batch_size,
                                  epochs=epochs,
                                  verbose=1,
                                  validation_data=([x1_valid, x2_valid], y_valid),
                                  shuffle=True)
  </code></pre>
  
  <p>it complains </p>
  
  <pre><code>AttributeError: 'list' object has no attribute 'shape'
  </code></pre>