code: def test_accepts_complex_dynamic_exec_prop_placeholder(self):
      compiler_utils.validate_exec_property_placeholder(
          "testkey",
          Channel(type=_MyType).future()[0].value
          + "foo"
          + ph.input("someartifact").uri
          + "/somefile.txt",
      )
  
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 3 for calling the ValidateExecPropertyPlaceholderTest obj's underlying member method code with example usage: obj.test_accepts_complex_dynamic_exec_prop_placeholder() without return types