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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_query_spec(cls, params):
 """Construct a model.QuerySpec from model.MapperSpec."""

    entity_kind = params[cls.ENTITY_KIND_PARAM]
    filters = params.get(cls.FILTERS_PARAM)
    app = params.get(cls._APP_PARAM)
    ns = params.get(cls.NAMESPACE_PARAM)

    return model.QuerySpec(
        entity_kind=cls._get_raw_entity_kind(entity_kind),
        keys_only=bool(params.get(cls.KEYS_ONLY_PARAM, False)),
        filters=filters,
        batch_size=int(params.get(cls.BATCH_SIZE_PARAM, cls._BATCH_SIZE)),
        model_class_path=entity_kind,
        app=app,
        ns=ns)