code: def add_pii_permissions(self, group, view_only=None):
          
          pii_model_names = [m.split(".")[1] for m in self.pii_models]
          if view_only:
              permissions = Permission.objects.filter(
                  (Q(codename__startswith="view") | Q(codename__startswith="display")),
                  content_type__model__in=pii_model_names,
              )
          else:
              permissions = Permission.objects.filter(
                  content_type__model__in=pii_model_names
              )
          for permission in permissions:
              group.permissions.add(permission)
  
          for model in self.pii_models:
              permissions = Permission.objects.filter(
                  codename__startswith="view",
                  content_type__app_label=model.split(".")[0],
                  content_type__model=f"historical{model.split('.')[1]}",
              )
              for permission in permissions:
                  group.permissions.add(permission)
  
          for permission in Permission.objects.filter(
              content_type__app_label="edc_registration",
              codename__in=[
                  "add_registeredsubject",
                  "delete_registeredsubject",
                  "change_registeredsubject",
              ],
          ):
              group.permissions.remove(permission)
          permission = Permission.objects.get(
              content_type__app_label="edc_registration",
              codename="view_historicalregisteredsubject",
          )
          group.permissions.add(permission)
docs: Adds PII model permissions.