for date in dates:
if isinstance(date, datetime):
if date.tzinfo is None: date = date.replace(tzinfo = default)
date = date.astimezone(vobject.icalendar.utc)
for date in dates:
if isinstance(date, datetime):
if date.tzinfo is None: date = date.replace(tzinfo = default)
date = date.astimezone(vobject.icalendar.utc)