def get_process_threads(self):
        """Return the number of threads belonging to the process."""
        rawlist = _psutil_bsd.get_process_threads(self.pid)
        retlist = []
        for thread_id, utime, stime in rawlist:
            ntuple = nt_thread(thread_id, utime, stime)
            retlist.append(ntuple)
        return retlist
Return the number of threads belonging to the process.