Does pybind11 default arugments expression been called every time when the python API invoked?

[linrongbin16]

I'm trying to add an expression as default arguments to my python function API, which is implemented by pybind11.

For example, here's the C++ function:

void my_print(std::chrono::system_clock::time_point tp = std::chrono::system_clock::now()) {
  std::cout << tp << std::endl;
}

PYBIND11_MODULE(my_module, m) {
  m.doc() = "my python module implement in pybind11";
  m.def("my_print", &my_print, py::arg("tp") = std::chrono::system_clock::now());
}

Now I'm wonderring that, the expression = std::chrono::system_clock::now(), I want it been called everytime I invoke this my_print API in python script.

But I'm not sure, is this expression been called everytime this API been invoked in python ? Or this expression is only been called once when this python module been load in python ?