Install Jupyterlab with previous Jupyter Noteboook

This question originally posted on Jupyterlab issue #7716. Sorry for reading the Getting help section late.

I installed Jupyter Notebook (5.2.2) via ubuntu repository (I am on Pop_OS 18.04) and want to enable jupyter lab. I can install Jupyterlab via pip3, but I want to install it this way to avoid dual package manager.

Typing
jupyter serverextension enable --py jupyterlab --sys-prefix
on terminal returned:

Traceback (most recent call last):
  File "/usr/bin/jupyter-serverextension", line 11, in <module>
    load_entry_point('notebook==5.2.2', 'console_scripts', 'jupyter-serverextension')()
  File "/usr/lib/python3/dist-packages/jupyter_core/application.py", line 266, in launch_instance
    return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
  File "/usr/lib/python3/dist-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/usr/lib/python3/dist-packages/notebook/serverextensions.py", line 293, in start
    super(ServerExtensionApp, self).start()
  File "/usr/lib/python3/dist-packages/jupyter_core/application.py", line 255, in start
    self.subapp.start()
  File "/usr/lib/python3/dist-packages/notebook/serverextensions.py", line 210, in start
    self.toggle_server_extension_python(arg)
  File "/usr/lib/python3/dist-packages/notebook/serverextensions.py", line 199, in toggle_server_extension_python
    m, server_exts = _get_server_extension_metadata(package)
  File "/usr/lib/python3/dist-packages/notebook/serverextensions.py", line 327, in _get_server_extension_metadata
    m = import_item(module)
  File "/usr/lib/python3/dist-packages/traitlets/utils/importstring.py", line 42, in import_item
    return __import__(parts[0])
ModuleNotFoundError: No module named 'jupyterlab'

Anyone has had this error before?

Kind regards,
Iwan

I decided to install via pip3.
I worried that the pip3 method will install their own library like anaconda does,
but it seems that is not the case.

Kind regards,
Iwan