def get_total_time(self):
        """Computes the sum of the total time across all contained timings.

        Returns
        -------
        res: float or None
            Returns the total number of seconds or None if no timings were
            recorded
        """
        if self._records:
            return sum(r.timings.get_total_time() for r in self._records)
        else:
            return None
Computes the sum of the total time across all contained timings.

        Returns
        -------
        res: float or None
            Returns the total number of seconds or None if no timings were
            recorded
        
numba/misc/llvm_pass_timings.py