pybind11 cast to py::object subclass is lazy

test.cpp

#include <pybind11/pybind11.h>
#include <iostream>
namespace py = pybind11;
int main() {
  Py_Initialize();
  auto gil = PyGILState_Ensure();
  PyObject *l = PyFloat_FromDouble(3.14);
  //PyObject *l = PyBytes_FromString("foo");
  auto n = py::cast<py::bytes>(l);
  std::cerr << "No problem yet...\n";
  std::cerr << static_cast<std::string>(n);
  PyGILState_Release(gil);
  return 0;
}