code: def define_tables(cls, metadata):
      global users, addresses
      users = Table(
          "users",
          metadata,
          Column("id", Integer, primary_key=True),
          Column("name", String(50)),
      )
      addresses = Table(
          "addresses",
          metadata,
          Column("id", Integer, primary_key=True),
          Column("email", String(50)),
          Column("user_id", Integer, ForeignKey("users.id")),
      )
  
imports: from sqlalchemy import desc
  from sqlalchemy import ForeignKey
  from sqlalchemy import func
  from sqlalchemy import Integer
  from sqlalchemy import join
  from sqlalchemy import literal_column
  from sqlalchemy import MetaData
  from sqlalchemy import select
  from sqlalchemy import String
  from sqlalchemy import testing
  from sqlalchemy.ext import serializer
  from sqlalchemy.orm import aliased
  from sqlalchemy.orm import class_mapper
  from sqlalchemy.orm import column_property
  from sqlalchemy.orm import configure_mappers
  from sqlalchemy.orm import joinedload
  from sqlalchemy.orm import relationship
  from sqlalchemy.orm import scoped_session
  from sqlalchemy.orm import sessionmaker
  from sqlalchemy.testing import AssertsCompiledSQL
  from sqlalchemy.testing import eq_
  from sqlalchemy.testing import fixtures
  from sqlalchemy.testing.entities import ComparableEntity
  from sqlalchemy.testing.schema import Column
  from sqlalchemy.testing.schema import Table
label_desc: Use image node_id 1 for calling the SerializeTest obj's underlying member method code with example usage: obj.define_tables(cls, metadata) without return types