When executing the cmd:

o365 spo listitem add --webUrl https://onenil.sharepoint.com/sites/utasdev01 --listId 973042c5-1d47-4d5b-90b1-2d4801406b41 --Title 'Çreated with office365-cli'

.. this error is returned:

Error: The expression "web/lists/(guid'973042c5-1d47-4d5b-90b1-2d4801406b41')/contenttypes" is not valid.

This can be assigned to me for a resolution. The same fix detailed in commits on #465 spo listitem get and #454 spo listitem set will be applied.