Filter between NumPy array and C++ class

class Convert_MyArray
{
 public:
  Convert_MyArray();

  // borrow data:
  PyObject*        my2py (MyArray<double>& a);
  MyArray<double>* py2my (PyObject* a);

  // copy data:
  PyObject*        my2py_copy (MyArray<double>& a);
  MyArray<double>* py2my_copy (PyObject* a);

  // print array:
  void             dump(MyArray<double>& a);

  // convert Py function to C/C++ function calling Py:
  Fxy              set_pyfunc (PyObject* f);
 protected:
  static PyObject* _pyfunc_ptr;  // used in _pycall
  static double    _pycall (double x, double y);
};