code: def testClassifierSerialization():
      spark = test_helpers.getOrCreateSparkSession(
          test_helpers.getCurrentMethodName()
      )
      import catboost_spark
  
      serializationDir = tempfile.mkdtemp(prefix="catboost_models_")
  
      path = os.path.join(serializationDir, "serialized_classifier_0")
  
      classifier = catboost_spark.CatBoostClassifier()
      classifier.write().overwrite().save(path)
      loadedClassifier = catboost_spark.CatBoostClassifier.load(path)
  
      path = os.path.join(serializationDir, "serialized_classifier_1")
  
      classifier = (
          catboost_spark.CatBoostClassifier()
          .setLossFunction("MultiClass")
          .setIterations(2)
      )
      classifier.write().overwrite().save(path)
      loadedClassifier = catboost_spark.CatBoostClassifier.load(path)
  
      shutil.rmtree(serializationDir)
  
imports: import collections
  import os
  import shutil
  import tempfile
  import test_helpers
  import pool_test_helpers
  from pyspark.ml import Pipeline, PipelineModel
  import pyspark.ml.evaluation
  from pyspark.ml.feature import StringIndexer, VectorAssembler
  from pyspark.ml.linalg import Vectors, VectorUDT
  import pyspark.ml.tuning
  from pyspark.sql import Row
  from pyspark.sql.types import *
label_desc: Use image node_id 7 for calling a global function with example usage: testClassifierSerialization() without return types