code: def test_preprocessing(self):
      distributions = {}
      distributions["0"] = {"mean": 0, "stddev": 1}
      distributions["1"] = {"mean": 4, "stddev": 3}
  
      def get_random_feature():
          return {
              k: np.random.normal(
                  loc=info["mean"], scale=info["stddev"]
              )
              for k, info in distributions.items()
          }
  
      data = [(i, get_random_feature()) for i in range(NUM_ROWS)]
      df = self.sc.parallelize(data).toDF(["i", COL_NAME])
      df.show()
  
      df.createOrReplaceTempView(TABLE_NAME)
  
      num_samples = NUM_ROWS // 2
      preprocessing_options = PreprocessingOptions(
          num_samples=num_samples
      )
  
      table_spec = TableSpec(table_name=TABLE_NAME)
  
      normalization_params = identify_normalization_parameters(
          table_spec,
          COL_NAME,
          preprocessing_options,
          seed=self.test_class_seed,
      )
  
      logger.info(normalization_params)
      for k, info in distributions.items():
          logger.info(
              f"Expect {k} to be normal with "
              f"mean {info['mean']}, stddev {info['stddev']}."
          )
          assert normalization_params[k].feature_type == CONTINUOUS
          assert (
              abs(normalization_params[k].mean - info["mean"]) < 0.05
          ), f"{normalization_params[k].mean} not close to {info['mean']}"
          assert abs(
              normalization_params[k].stddev - info["stddev"] < 0.2
          ), f"{normalization_params[k].stddev} not close to {info['stddev']}"
      logger.info("identify_normalization_parameters seems fine.")
  
file_path: ReAgent/reagent/test/workflow/test_preprocessing.py
imports: import logging
  import unittest
  import numpy
  import pytest
  from reagent.preprocessing.identify_types import CONTINUOUS
  from reagent.test.workflow.reagent_sql_test_base import ReagentSQLTestBase
  from reagent.workflow.identify_types_flow import identify_normalization_parameters
  from reagent.workflow.types import PreprocessingOptions, TableSpec
label_desc: Use image node_id 2 for calling the TestPreprocessing obj's underlying member method code with example usage: obj.test_preprocessing() and returns: unknown