docs: def init_model(engine, create=True, drop=False):
      """
      Initializes the shared SQLAlchemy state in the L{coilmq.store.sa.model} module.
  
      @param engine: The SQLAlchemy engine instance.
      @type engine: C{sqlalchemy.Engine}
  
      @param create: Whether to create the tables (if they do not exist).
      @type create: C{bool}
  
      @param drop: Whether to drop the tables (if they exist).
      @type drop: C{bool}
      """
      meta.engine = engine
      meta.metadata = MetaData(bind=meta.engine)
      meta.Session = scoped_session(sessionmaker(bind=meta.engine))
      model.setup_tables(create=create, drop=drop)