I'm trying to use the python api from an enterprise (UC Berkeley) but can't figure out how to authenticate with the GIS() function since I don't have a password and for the web access authenticate through our enterprise login.
Please refer to the documentation below, which lists examples for each of Portal's authentication schemes.
Working with different authentication schemes
Since you do not log into Portal with a password, you are most likely using Integrated Windows Authentication or SAML.
Integrated Windows Authentication