cool, well... connecting to a portal can be done a few ways. with a local account:
from arcgis.gis import GIS
portalGIS = GIS("https://your portal", 'username', "password")
dataitem = portalGIS.content.get('the id of the table that you want to get')
Using oauth takes some steps to get set up, provided here which involves creating an Application to set up an client id.
client_id = 'you have to creat it to get it'
portalGIS = GIS(client_id=client_id, url='your portal stuff')
dataitem = portalGIS.content.get('the id of the table that you want to get')
... this will prompt the user to connect though, and required a generated key to be pasted last time I ran it. If you want it hands free automated, setting up the local portal account would work easiest.
Is the data shared at a level where you can get it?