Allow TimeLogger.log to be called with default arguments.
Without this fix, the build_candidates script crashes on line 86
(if it takes long enough for this line to be reached).
@@ -247,6 +247,7 @@ class TimeLogger:
done = done.value()
self.tot_time += self.timer.time()
self.timer.reset()
+ if report:
report['exs'] = done
if total > 0 and done > 0:
progress = done / total
