Cleaned up use of context manager in SQLite schema editor

            yield

            model._meta.db_table = original_table_name

        # Rename the old table to something temporary

        old_table_name = model._meta.db_table + "__old"

        with altered_table_name(model, old_table_name):

        with altered_table_name(model, model._meta.db_table + "__old"):

            # Rename the old table to make way for the new

            self.alter_db_table(model, temp_model._meta.db_table, model._meta.db_table)

        # Create a new table with that format. We remove things from the

        # deferred SQL that match our table name, too

            # Create a new table with the updated schema. We remove things

            # from the deferred SQL that match our table name, too

            self.deferred_sql = [x for x in self.deferred_sql if temp_model._meta.db_table not in x]

            self.create_model(temp_model)

        # Copy data from the old table

            # Copy data from the old table into the new table

            field_maps = list(mapping.items())

            self.execute("INSERT INTO %s (%s) SELECT %s FROM %s" % (

                self.quote_name(temp_model._meta.db_table),

                ', '.join(self.quote_name(x) for x, y in field_maps),

                ', '.join(y for x, y in field_maps),

            self.quote_name(old_table_name),

                self.quote_name(model._meta.db_table),

            ))

            # Delete the old table

        with altered_table_name(model, old_table_name):

            self.delete_model(model, handle_autom2m=False)

        # Run deferred SQL on correct table