Method contains

include/pybind11/pytypes.h:2328–2334

    bool empty() const { return size() == 0; }
    template <typename T>
    bool contains(T &&val) const {
        auto result = PySet_Contains(m_ptr, detail::object_or_cast(std::forward<T>(val)).ptr());
        if (result == -1) {
            throw error_already_set();
        }
        return result == 1;
    }
};

class set : public anyset {