code: def testCheckPipelinExistenceRequiredMigrated(self):
      flags_dict = {
          labels.ENGINE_FLAG: "beam",
          labels.PIPELINE_NAME: "pipeline",
      }
      handler = FakeHandler(flags_dict)
      old_path = os.path.join(os.environ["HOME"], "beam", "pipeline")
      new_path = os.path.join(
          os.environ["HOME"], "tfx", "beam", "pipeline"
      )
  
      fileio.makedirs(old_path)
      self.assertFalse(fileio.exists(new_path))
  
      handler._check_pipeline_existence(
          flags_dict[labels.PIPELINE_NAME]
      )
  
      self.assertTrue(fileio.exists(new_path))
      self.assertFalse(fileio.exists(old_path))
  
imports: import os
  import textwrap
  import tensorflow
  from tfx.dsl.io import fileio
  from tfx.tools.cli import labels
  from tfx.tools.cli.handler import base_handler
label_desc: Use image node_id 7 for calling the BaseHandlerTest obj's underlying member method code with example usage: obj.testCheckPipelinExistenceRequiredMigrated() without return types