Empty initializer list warning

[kwabenantim]

Summary

Empty initializer lists {} like

.def(py::init<::std::vector<Foo *> >(), py::arg("laminas") = {})

generate a warning

error: converting to ‘pybind11::arg’ from initializer list would use explicit 
constructor ‘constexpr pybind11::arg::arg(const char*)’ [-Werror]                                                                                                ^
note: in C++11 and above a default constructor can be explicit
cc1plus: all warnings being treated as errors

Possible fix:

.def(py::init<::std::vector<Foo *> >(), py::arg("laminas") = std::vector<Foo *>{})