Performance and dates

Out of these timezones in UTC = timezone('UTC')

    > Eastern = timezone('US/Eastern') Central =
    > timezone('US/Central') Mountain = timezone('US/Mountain')
    > Pacific = timezone('US/Pacific') London =
    > timezone('Europe/London') Paris = timezone('Europe/Paris')
    > Berlin = timezone('Europe/Berlin') Moscow =
    > timezone('Europe/Moscow')

    > As far as I can see the only timezones actually used are
    > UTC - as a function default value, and Pacific - used in
    > __main__ Is it OK to remove all the unused ones, or is
    > there something that relies on them?

Well, I provided these for convenience for people to import from the
dates module. It never occurred to me that simply instantiating 7
objects would carry such a performance hit. However, it doesn't
appear that I documented this anywhere, so it should be safe to remove
them - just make a note in the API_CHANGES file that they are gone and
I'll mention it in the release notes.