def execute_chooser(context):
    """statement execution chooser.

    given an :class:`.ORMExecuteState` for a statement, return a list
    of shards we should consult.

    As before, we want a "shard_id" execution option to be present.
    Otherwise, this would be a lazy load from a parent object where we
    will look for the previous token.

    """
    if context.lazy_loaded_from:
        return [context.lazy_loaded_from.identity_token]
    else:
        return [context.execution_options["shard_id"]]