docs: def download_log(currentfile=None):
      """downloads log of given .py file from EV3."""
  
      if currentfile == None:
          return
      
      # add ".err.log" if file doesn't end with it!
      if not currentfile.endswith(".err.log"):
          currentfile=currentfile + ".err.log"
      
      list = get_base_ev3dev_cmd() + ['download','--force']
      list.append(currentfile)
  
      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, "Downloading log of program from EV3", autoclose=True)
      dlg.wait_window()
      if dlg.returncode == 0:
          from pathlib import Path
          home = str(Path.home())
          open_file(currentfile,home,True)