I ended up using BeautifulSoup instead

    get_partyid = requests.post('%s' % nwsap_host, data=get_partyid)
    gpid = BeautifulSoup(get_partyid.content, 'xml')
    gpstatus = gpid.find('api:PlexViewResponse')
    print("Status:", gpstatus.attrs['Status'])
    PartyID = gpid.find('PartyId').get_text()
    print("PartyID:", PartyID)

Much easier to digest for me as a newbie.