Method GetMutable

catboost/libs/model/model.h:636–641

    }

    TModelTrees* GetMutable() {
        if (Trees.RefCount() > 1) {
            Trees = MakeAtomicShared<TModelTrees>(*Trees);
        }
        return Trees.Get();
    }
private:
    TAtomicSharedPtr<TModelTrees> Trees = MakeAtomicShared<TModelTrees>();
};