tests: fix merge mistake

Author: henryiii

tests/test_sequences_and_iterators.cpp

@@ -338,6 +338,7 @@ TEST_SUBMODULE(sequences_and_iterators, m) {
         }, py::keep_alive<0, 1>())
         .def("nonzero_values", [](const IntPairs& s) {
             return py::make_value_iterator(NonZeroIterator<std::pair<int, int>>(s.begin()), NonZeroSentinel());
+        }, py::keep_alive<0, 1>())
         .def("simple_iterator", [](IntPairs& self) {
             return py::make_iterator(self);
         }, py::keep_alive<0, 1>())