In the ArcGIS API for Python Reference documentation, the sort_field parameter in the create() method for GroupManager lacks a list of choices available.
https://developers.arcgis.com/python/api-reference/arcgis.gis.toc.html?#arcgis.gis.GroupManager.crea...
From altering manually and checking the JSON I believe the options here are; title, owner, modified, numviews
