Update model.py

In response to reviewer's comments.

namignizer/model.py

@@ -37,11 +37,14 @@ class NamignizerModel(object):
         self._weights = tf.placeholder(tf.float32, [batch_size * num_steps])
 
         # lstm for our RNN cell (GRU supported too)
+        lstm_cells = []
+        for layer in range(config.num_layers):
             lstm_cell = tf.contrib.rnn.BasicLSTMCell(size, forget_bias=0.0)
             if is_training and config.keep_prob < 1:
                 lstm_cell = tf.contrib.rnn.DropoutWrapper(
                     lstm_cell, output_keep_prob=config.keep_prob)
-        cell = tf.contrib.rnn.MultiRNNCell([lstm_cell] * config.num_layers)
+            lstm_cells.append(lstm_cell)
+        cell = tf.contrib.rnn.MultiRNNCell(lstm_cells)
 
         self._initial_state = cell.zero_state(batch_size, tf.float32)