code: def test_always_changed(dvc):
      stage = create_stage(
          PipelineStage, dvc, outs=["output"], deps=["input"], **kwargs
      )
      assert (
          stage.PARAM_ALWAYS_CHANGED
          not in to_pipeline_file(stage)["something"]
      )
  
      stage = create_stage(
          PipelineStage, dvc, **kwargs, always_changed=True
      )
      assert (
          to_pipeline_file(stage)["something"][
              stage.PARAM_ALWAYS_CHANGED
          ]
          is True
      )
  
imports: import os
  import pytest
  from voluptuous import Schema
  from dvc import output
  from dvc.dvcfile import PROJECT_FILE
  from dvc.schema import SINGLE_PIPELINE_STAGE_SCHEMA
  from dvc.stage import PipelineStage, create_stage
  from dvc.stage.serialize import to_pipeline_file
label_desc: Use image node_id 12 for calling a global function with example usage: test_always_changed(dvc) without return types