docs: def cleanup_files_on_ev3():
      """cleanup files in homedir on EV3."""
  
      list = get_base_ev3dev_cmd() + ['cleanup']
  
      env = os.environ.copy()
      env["PYTHONUSERBASE"] = THONNY_USER_BASE
      proc = subprocess.Popen(list, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
                              universal_newlines=True, env=env)
      dlg = MySubprocessDialog(get_workbench(), proc, "Delete files in homedir on EV3", autoclose=False)
      dlg.wait_window()