title: 'tuple' object has no attribute 'shape'
body: <p>I am running this code in Google Colab and I get this error</p>
  <p>This is the code link to Google Colab:</p>
  <h2><a href="https://colab.research.google.com/drive/1DbeK9Qz_Q31gM6lmERNOaegP2irTuv0a?usp=sharing" rel="nofollow noreferrer">https://colab.research.google.com/drive/1DbeK9Qz_Q31gM6lmERNOaegP2irTuv0a?usp=sharing</a></h2>
  <p>And this is the error:</p>
  <pre><code>AttributeError                            Traceback (most recent call last)
  &lt;ipython-input-7-e258b3312a90&gt; in &lt;module&gt;()
       31 print(f&quot;acc: {val_acc}&quot;)
       32 
  ---&gt; 33 predictions = model.predict([x_test])
       34 
       35 print(np.argmax(predictions[0]))
  
  10 frames
  /usr/local/lib/python3.6/dist-packages/tensorflow/python/framework/func_graph.py in wrapper(*args, **kwargs)
      966           except Exception as e:  # pylint:disable=broad-except
      967             if hasattr(e, &quot;ag_error_metadata&quot;):
  --&gt; 968               raise e.ag_error_metadata.to_exception(e)
      969             else:
      970               raise
  
  AttributeError: in user code:
  
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:1147 predict_function  *
          outputs = self.distribute_strategy.run(
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:951 run  **
          return self._extended.call_for_each_replica(fn, args=args, kwargs=kwargs)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:2290 call_for_each_replica
          return self._call_for_each_replica(fn, args, kwargs)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:2649 _call_for_each_replica
          return fn(*args, **kwargs)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:1122 predict_step  
          return self(x, training=False)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/base_layer.py:927 __call__
          outputs = call_fn(cast_inputs, *args, **kwargs)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/sequential.py:291 call
          outputs = layer(inputs, **kwargs)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/base_layer.py:927 __call__
          outputs = call_fn(cast_inputs, *args, **kwargs)
      /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/layers/core.py:642 call
          input_shape = inputs.shape
  
      AttributeError: 'tuple' object has no attribute 'shape'
  </code></pre>