Internal version of `display`.

  Args:
    port: As with `display`.
    height: As with `display`.
    print_message: True to print which TensorBoard instance was selected
      for display (if applicable), or False otherwise.
    display_handle: If not None, an IPython display handle into which to
      render TensorBoard.

def _display(port=None, height=None, print_message=False, display_handle=None):
  """Internal version of `display`.

  Args:
    port: As with `display`.
    height: As with `display`.
    print_message: True to print which TensorBoard instance was selected
      for display (if applicable), or False otherwise.
    display_handle: If not None, an IPython display handle into which to
      render TensorBoard.
  """
  if height is None:
    height = 800

  if port is None:
    infos = manager.get_all()
    if not infos:
      raise ValueError("Can't display TensorBoard: no known instances running.")
    else:
      info = max(manager.get_all(), key=lambda x: x.start_time)
      port = info.port
  else:
    infos = [i for i in manager.get_all() if i.port == port]
    info = (
        max(infos, key=lambda x: x.start_time)
        if infos
        else None
    )

  if print_message:
    if info is not None:
      message = (
          "Selecting TensorBoard with {data_source} "
          "(started {delta} ago; port {port}, pid {pid})."
      ).format(
          data_source=manager.data_source_from_info(info),
          delta=_time_delta_from_info(info),
          port=info.port,
          pid=info.pid,
      )
      print(message)
    else:
      # The user explicitly provided a port, and we don't have any
      # additional information. There's nothing useful to say.
      pass

  fn = {
      _CONTEXT_COLAB: _display_colab,
      _CONTEXT_IPYTHON: _display_ipython,
      _CONTEXT_NONE: _display_cli,
  }[_get_context()]
  return fn(port=port, height=height, display_handle=display_handle)