inserting xml-snippet into docx using the python-docx api

We need to change header text-orientation of tables. We are aware that this may not be possible with the current state of the API.  We identify the xml-snippet to be inserted using opc-diag as suggested elsewhere. Can we use xml-snippet insertion to achieve this? If yes what is the API-command to do the xml-insertion at a specific point of the docx?
-- sub
