code: def testBuildChannelToKeyFn(self):
      model = types.Channel(
          type=standard_artifacts.Model,
          producer_component_id="trainer",
          output_key="model",
      )
      examples = types.Channel(
          type=standard_artifacts.Examples,
          producer_component_id="example_gen",
          output_key="examples",
      )
  
      fn = compiler_utils.build_channel_to_key_fn(
          {"_trainer.model": "real_key"}
      )
      self.assertEqual(fn(model), "real_key")
      self.assertEqual(fn(examples), "_example_gen.examples")
  
imports: import itertools
  import tensorflow
  from tfx import types
  from tfx.components import CsvExampleGen
  from tfx.components import StatisticsGen
  from tfx.dsl.compiler import compiler_utils
  from tfx.dsl.components.base import base_component
  from tfx.dsl.components.base import base_executor
  from tfx.dsl.components.base import executor_spec
  from tfx.dsl.components.common import importer
  from tfx.dsl.components.common import resolver
  from tfx.dsl.input_resolution.strategies import latest_blessed_model_strategy
  from tfx.dsl.placeholder import placeholder
  from tfx.orchestration import pipeline
  from tfx.proto.orchestration import pipeline_pb2
  from tfx.types import standard_artifacts
  from tfx.types.artifact import Artifact
  from tfx.types.artifact import Property
  from tfx.types.artifact import PropertyType
  from tfx.types.channel import Channel
  from tfx.types.channel import OutputChannel
  from tfx.types.channel_utils import external_pipeline_artifact_query
  from google.protobuf import text_format
  from ml_metadata.proto import metadata_store_pb2
label_desc: Use image node_id 11 for calling the CompilerUtilsTest obj's underlying member method code with example usage: obj.testBuildChannelToKeyFn() without return types