Fetch a site user custom property defined at the site level.

Arguments:

def api.resources.site_user_custom_property(
  name: <str> = None,
  user_id: <str> = None,
):

Returns a str, dec, bool, or None depending on the custom property's definition.

Example:

prop = api.sites.site_user_custom_property(name="foo", user_id="bar")