code: def test_serialization(classification_model):
      rms = RMSprop()
      classification_model.compile(
          rms, "categorical_crossentropy", ["acc"]
      )
      spark_model = SparkMLlibModel(
          classification_model,
          frequency="epoch",
          mode="synchronous",
          num_workers=2,
      )
      spark_model.save("test.h5")
      loaded_model = load_spark_model("test.h5")
      assert loaded_model.master_network.to_json()
  
imports: from tensorflow.keras.optimizers import RMSprop
  from elephas.spark_model import SparkMLlibModel, load_spark_model
  from elephas.utils.rdd_utils import to_labeled_point
label_desc: Use image node_id 1 for calling a global function with example usage: test_serialization(classification_model) without return types