docs: def has_cwd(state, dir, incorrect_msg="Your current working directory should be `{{dir}}`. Use `cd {{dir}}` to navigate there."):
      """Check whether the student is in the expected directory.
  
      This check is typically used before using ``has_expr_output()``
      to make sure the student didn't navigate somewhere else.
  
      Args:
          state: State instance describing student and solution code. Can be omitted if used with ``Ex()``.
          dir: Directory that the student should be in. Always use the absolute path.
          incorrect_msg: If specified, this overrides the automatically generated message in
                         case the student is not in the expected directory.
  
      :Example:
  
          If you want to be sure that the student is in ``/home/repl/my_dir``: ::
  
              Ex().has_cwd('/home/repl/my_dir')
  
      """
      expr = "[[ $PWD == '{}' ]]".format(dir)
      _msg = state.build_message(incorrect_msg, fmt_kwargs={ 'dir': dir })
      has_expr_exit_code(state, expr, output="0", incorrect_msg=_msg)
      return state