[QUESTION] How can I overload the [ ] operator?

I understand how the other operators are overloaded but I'm having difficulty with this one.
This is my code (simplified):

float& Vec::operator[](unsigned i)
{
    return privatedata[i];
}

py::class_<Vec>(m, "Vec")
      .def(py::init<unsigned &>())
      .def(unsigned() [] float());

It may not come as a surprise that this does not work. Since a Vec object is not passed in or out of the operator directly, my binding cannot contain py::self. Please let me know what I'm doing wrong! Thanks everyone.

The issue names no repository files, tests, or entry points. Start by determining whether a documentation example or another repository change is wanted; done should be a maintainer-approved explanation of how this operator binding should be handled.