Print elapsed time and message.

def hms(self, msg, tic=None, prt=sys.stdout):
        """Print elapsed time and message."""
        if tic is None:
            tic = self.tic
        now = timeit.default_timer()
        hms = str(datetime.timedelta(seconds=(now-tic)))
        prt.write('{HMS}: {MSG}\n'.format(HMS=hms, MSG=msg))
        return now