title: "Merge" replacement Keras/Tensorflow/Python3
body: <p>Merge is not running with Keras/Tensorflow/Python3 version. With previous versions, Merge was running.
  But now, it is not running. So I think I should convert this code with replacement "Merge". "Merge" is missing in new Keras/Tensorflow/Python3 version. </p>
  
  <p>How can I rewrite Merge(..., mode='ave') and Merge(...,mode='concat') ?</p>
  
  <p>My code part is below :</p>
  
  <pre><code>...
  
  from keras.layers import Merge
  ...
  left_branch = Sequential()
  left_branch.add(Convolution3D...
  ...
  right_branch = Sequential()
  right_branch.add(Convolution3D...
  ...
  merged = Merge([left_branch, right_branch], mode='ave')
  lstm_branch = Sequential()
  lstm_branch.add(Embedding(input_dim=7, output_dim=8, input_length=7))
  lstm_branch.add(LSTM(output_dim=8, input_shape=(7, ) ))
  lstm_branch.add(Dense(32, activation='relu'))
  
  model = Sequential()
  model.add(merged)
  merged_2 = Merge([model, lstm_branch], mode='concat')
  model_2 = Sequential()
  model_2.add(merged_2)
  model_2.add(Dense(nb_classes,init='normal'))
  model_2.add(Activation('softmax'))
  model_2.compile(loss='categorical_crossentropy', optimizer='RMSprop', metrics=['accuracy'])
  </code></pre>