class_docstr: Helper methods for Airflow Handler.
class_docstr_tok: ["Helper","methods","for","Airflow","Handler","."]
docstr: List all the pipelines in the environment.
docstr_tok: ["List","all","the","pipelines","in","the","environment","."]
code: def list_pipelines(self) -> None:
      """List all the pipelines in the environment."""
      if not fileio.exists(self._handler_home_dir):
          click.echo("No pipelines to display.")
          return
  
      pipelines_list = fileio.listdir(self._handler_home_dir)
  
      # Print every pipeline name in a new line.
      click.echo("-" * 30)
      click.echo("\n".join(pipelines_list))
      click.echo("-" * 30)
  
imports: import json
  import os
  import subprocess
  from typing import Any, Dict, List
  import click
  from tfx.dsl.io import fileio
  from tfx.tools.cli import labels
  from tfx.tools.cli.handler import airflow_dag_runner_patcher
  from tfx.tools.cli.handler import base_handler
  from tfx.utils import io_utils
label_desc: Use image node_id 6 for calling the AirflowHandler obj's underlying member method code with example usage: obj.list_pipelines() without return types