The if-else cases in lsqr.py were not exhaustive. They become exhaustive by changing ab > aa to ab >= aa.
#ifndef __PYTHON_BIRTHID_H__
#define __PYTHON_BIRTHID_H__
#include <boost/python.hpp>
namespace dionysus {
namespace python {
//typedef int BirthID;
//typedef boost::python::long_ BirthID;
typedef boost::python::object BirthID;
} } // namespace dionysus::python
#endif // __PYTHON_BIRTHID_H__