pytz.timezone() should also catch the IOError and throw a pytz.UnknownTimeZoneError even though it is very unlikely to occur if pytz.all_timezones_set is clean, but that also depends on whether they are preloaded or if all_timezones_set is just verified with os.path.isfile().
pytz.timezone() should also catch the IOError and throw a pytz.UnknownTim eZoneError even though it is very unlikely to occur if pytz.all_ timezones_ set is clean, but that also depends on whether they are preloaded or if all_timezones_set is just verified with os.path.isfile().