to<ToddCoxeter>(congruence_kind, FroidurePin, WordGraph) fails

[james-d-mitchell]

The following fails in v1.4.4:

S = FroidurePin(Transf([1, 3, 4, 2, 3]), Transf([3, 2, 1, 3, 3]))
to(congruence_kind.twosided, S, S.right_cayley_graph(), rtype=(ToddCoxeter,))

Even though there is a function in to-todd-coxeter.cpp:

    // WordGraph
    m.def("to_todd_coxeter_word",
          [](congruence_kind            knd,
             FroidurePinBase&           fpb,
             WordGraph<uint32_t> const& wg) {
            return to<ToddCoxeter<word_type>>(knd, fpb, wg);
          });
    m.def("to_todd_coxeter_string",
          [](congruence_kind            knd,
             FroidurePinBase&           fpb,
             WordGraph<uint32_t> const& wg) {
            return to<ToddCoxeter<std::string>>(knd, fpb, wg);
          });

[james-d-mitchell]

The error message is:

TypeError: to_todd_coxeter(): incompatible function arguments. The following argument types are supported:
    1. (arg0: _libsemigroups_pybind11.congruence_kind, arg1: _libsemigroups_pybind11.KnuthBendixStringRewriteFromLeft) -> _libsemigroups_pybind11.ToddCoxeterString
    2. (arg0: _libsemigroups_pybind11.congruence_kind, arg1: _libsemigroups_pybind11.KnuthBendixStringRewriteTrie) -> _libsemigroups_pybind11.ToddCoxeterString
    3. (arg0: _libsemigroups_pybind11.congruence_kind, arg1: _libsemigroups_pybind11.KnuthBendixWordRewriteFromLeft) -> _libsemigroups_pybind11.ToddCoxeterWord
    4. (arg0: _libsemigroups_pybind11.congruence_kind, arg1: _libsemigroups_pybind11.KnuthBendixWordRewriteTrie) -> _libsemigroups_pybind11.ToddCoxeterWord

Invoked with: <congruence_kind.onesided: 1>, <fully enumerated FroidurePin with 2 generators, 88 elements, Cayley graph ⌀ 9, & 18 rules>, <WordGraph with 88 nodes, 176 edges, & out-degree 2>

I think the issue is that there's a missing argument in the rtype kwarg:

to(congruence_kind.onesided, S, S.right_cayley_graph(), rtype=(ToddCoxeter,list[int]))

and that the error message is not helpful.