[x1798DE]

I think your concept of "dynamic" and "static" is exactly backwards from mine. datetime specifies an API (tzinfo) for dynamic objects, so that a single object provides the time zone information for many datetimes. pytz's localize function attaches a different static object to each datetime, depending on which one is appropriate.

pytz defaulting to the last offset instead of the first would cause a lot more silent breakages, because it would probably be right about half the time, and wrong about half the time, and even when it's wrong it won't be obvious. Defaulting to the first value in the list is as close as pytz can come to failing loudly without actually raising an exception, because it's obviously wrong nearly 100% of the time.

[mkesper]

Don't guess, fail explicitly.