message: make deep copy of axis parameter for batch norm
diff: @@ -141,6 +141,9 @@ class BatchNormalization(base.Layer):
  **kwargs):
  super(BatchNormalization, self).__init__(
  name=name, trainable=trainable, **kwargs)
  + if isinstance(axis, list):
  + self.axis = axis[:]
  + else:
  self.axis = axis
  self.momentum = momentum
  self.epsilon = epsilon
  