code: def _setup_once_tables(cls):
      if cls.run_define_tables == "once":
          cls.define_tables(cls._tables_metadata)
          if cls.run_create_tables == "once":
              cls._tables_metadata.create_all(cls.bind)
          cls.tables.update(cls._tables_metadata.tables)
          cls.sequences.update(cls._tables_metadata._sequences)
  
imports: from __future__ import annotations
  import itertools
  import random
  import re
  import sys
  import sqlalchemy
  from .base import TestBase
  from ..None import config
  from ..None import mock
  from ..assertions import eq_
  from ..assertions import ne_
  from ..util import adict
  from ..util import drop_all_tables_from_metadata
  from ...None import event
  from ...None import util
  from ...schema import sort_tables_and_constraints
  from ...sql import visitors
  from ...sql.elements import ClauseElement
label_desc: Use image node_id 6 for calling the TablesTest obj's underlying member method code with example usage: obj._setup_once_tables(cls) without return types