code: def mean_squared_error(y_true, y_pred):
      batch_size = y_true.shape.as_list()[0]
      batch_size_inv = 1 / batch_size
      out = y_true - y_pred
      out = out.square()
      mse_loss = out.reduce_sum(axis=0) * batch_size_inv
      return mse_loss
  
imports: import tf_encrypted
label_desc: Use image node_id 3 for calling a global function with example usage: mean_squared_error(y_true, y_pred) and returns: mse_loss