Method remove

src/CoolPropLib.cpp:493–499

        return next_handle - 1;
    }
    void remove(long handle) {
        std::scoped_lock guard(ASLib_mutex);
        std::size_t count_removed = ASlibrary.erase(handle);
        if (count_removed != 1) {
            throw CoolProp::HandleError("could not free handle");
        }
    }
    shared_ptr<CoolProp::AbstractState>& get(long handle) {
        std::scoped_lock guard(ASLib_mutex);
        auto it = ASlibrary.find(handle);