code: def _generate_delete_sql(self, delete_keys):
          
          for key in delete_keys:
              app_label, sql_name = key
              old_node = self.from_sql_graph.nodes[key]
              operation = DeleteSQL(sql_name, old_node.reverse_sql, reverse_sql=old_node.sql)
              sql_deps = [n.key for n in self.from_sql_graph.node_map[key].children]
              sql_deps.append(key)
              self.add_sql_operation(app_label, sql_name, operation, sql_deps)
docs: Generate forward delete operations for SQL items.