code: def materialized_cache(df: DataFrame) -> DataFrame:
      return (
          df.sql_ctx.createDataFrame(df.toPandas(), df.schema)
          .coalesce(1)
          .cache()
      )
  
imports: import os
  import tempfile
  import unittest
  from typing import Dict, Optional, Set, Type, Union
  from pandas.testing import assert_frame_equal
  from pyspark.sql import DataFrame, types, functions
  from synapse.ml.cyber.feature import indexers
  from synapse.ml.cyber import DataFactory
  from synapse.ml.cyber.anomaly.collaborative_filtering import AccessAnomaly, AccessAnomalyModel, AccessAnomalyConfig, ConnectedComponents, ModelNormalizeTransformer, _UserResourceFeatureVectorMapping
  from synapsemltest.cyber.explain_tester import ExplainTester
  from synapsemltest.spark import *
label_desc: Use image node_id 1 for calling a global function with example usage: materialized_cache(df) and returns: df