code: def test_empty_schema(default_model_storage: ModelStorage):
      empty_schema = GraphSchema({})
      runner = DaskGraphRunner(
          graph_schema=empty_schema,
          model_storage=default_model_storage,
          execution_context=ExecutionContext(
              graph_schema=empty_schema, model_id="1"
          ),
      )
      results = runner.run()
      assert not results
  
imports: from __future__ import annotations
  from typing import Optional
  import pytest
  from rasa.engine.graph import ExecutionContext, GraphSchema, SchemaNode
  from rasa.engine.exceptions import GraphRunError
  from rasa.engine.runner.dask import DaskGraphRunner
  from rasa.engine.storage.storage import ModelStorage
  from tests.engine.graph_components_test_classes import AddInputs, AssertComponent, ExecutionContextAware, ProvideX, SubtractByX, PersistableTestComponent
label_desc: Use image node_id 4 for calling a global function with example usage: test_empty_schema(default_model_storage) without return types