Refs #13637 -- Removed unused code in GenericRelatedObjectManager

from django.contrib.contenttypes.models import ContentType

from django.core import checks

from django.core.exceptions import FieldDoesNotExist, ObjectDoesNotExist

from django.db import DEFAULT_DB_ALIAS, connection, models, router, transaction

from django.db import DEFAULT_DB_ALIAS, models, router, transaction

from django.db.models import DO_NOTHING, signals

from django.db.models.base import ModelBase, make_foreign_order_accessors

from django.db.models.fields.related import (

            content_type = ContentType.objects.db_manager(instance._state.db).get_for_model(

                instance, for_concrete_model=rel.field.for_concrete_model)

            self.content_type = content_type

            qn = connection.ops.quote_name

            join_cols = rel.field.get_joining_columns(reverse_join=True)[0]

            self.source_col_name = qn(join_cols[0])

            self.target_col_name = qn(join_cols[1])

            self.content_type_field_name = rel.field.content_type_field_name

            self.object_id_field_name = rel.field.object_id_field_name

            self.prefetch_cache_name = rel.field.attname