'What to use to position Staff on the Map when not Tracking them
- valid options are:
"site_id" - Use the HR\'s Site Location
"person_id" - Use the HR\'s Person Location (i.e. Home Address)
("person_id", "site_id") - Use the HR\'s Person Location if-available, fallback to the Site if-not
("site_id","person_id") - Use the HR\'s Site Location if-available, fallback to the Person\'s Home Address if-not
NB This is read onaccept of editing Home Addresses & Assigning Staff to Sites so is not a fully-dynamic change
- onaccept is used for performance (avoiding joins)'

def get_hrm_location_staff(self):

    return self.hrm.get('location_staff', 'site_id')
