In your code list.start_time
returns start datetime as unicode string.
You need to convert it to datetime.timedelta
like
from dateutil import parser
and
for snap in snaps:
limit = datetime.now() - timedelta(days=14)
if parser.parse(snap.start_time).date() <= limit.date():
#do your filter stuff here
print conn.delete_snapshot(snap.id)
Note: First you can try with print snap.id
, if it will return a valid result then you can do print conn.delete_snapshot(snap.id)