code: def _get_common_variables(dataset, force_tf_compat_v1):
      """Returns metadata schema, preprocessing fn, input dataset metadata."""
  
      tf_metadata_schema = benchmark_utils.read_schema(
          dataset.tf_metadata_schema_path()
      )
  
      preprocessing_fn = dataset.tft_preprocessing_fn()
  
      feature_spec = schema_utils.schema_as_feature_spec(
          tf_metadata_schema
      ).feature_spec
      type_spec = impl_helper.get_type_specs_from_feature_specs(
          feature_spec
      )
      transform_input_columns = tft.get_transform_input_columns(
          preprocessing_fn,
          type_spec,
          force_tf_compat_v1=force_tf_compat_v1,
      )
      transform_input_dataset_metadata = (
          dataset_metadata.DatasetMetadata(
              schema_utils.schema_from_feature_spec(
                  {
                      feature: feature_spec[feature]
                      for feature in transform_input_columns
                  }
              )
          )
      )
      tfxio = tf_example_record.TFExampleBeamRecord(
          physical_format="tfexamples",
          schema=transform_input_dataset_metadata.schema,
          telemetry_descriptors=["TFTransformBenchmark"],
      )
  
      return CommonVariablesTuple(
          tf_metadata_schema=tf_metadata_schema,
          preprocessing_fn=preprocessing_fn,
          transform_input_dataset_metadata=transform_input_dataset_metadata,
          tfxio=tfxio,
      )
  
imports: import collections
  import shutil
  import tempfile
  import time
  from absl import logging
  import apache_beam
  from apache_beam.utils import shared
  import tensorflow
  import tensorflow_transform
  from tensorflow_transform import graph_tools
  from tensorflow_transform import impl_helper
  import tensorflow_transform.beam
  from tensorflow_transform.beam import impl
  from tensorflow_transform.saved import saved_transform_io
  from tensorflow_transform.saved import saved_transform_io_v2
  from tensorflow_transform.tf_metadata import dataset_metadata
  from tensorflow_transform.tf_metadata import schema_utils
  import tfx
  from tfx.benchmarks import benchmark_utils
  from tfx.benchmarks import benchmark_base
  from tfx_bsl.coders import example_coder
  from tfx_bsl.tfxio import tensor_adapter
  from tfx_bsl.tfxio import tf_example_record
label_desc: Use image node_id 1 for calling a global function with example usage: _get_common_variables(dataset, force_tf_compat_v1) and returns: CommonVariablesTuple