from boto3.session import Session


session = Session(aws_access_key_id='auth',
              aws_secret_access_key='auth')
s3 = session.resource("s3")

get_last_modified = lambda obj: int(obj.last_modified.strftime('%s'))

bckt = s3.Bucket("global-jobs-storage")
objs = [obj for obj in bckt.objects.all()]

objs = [obj for obj in sorted(objs, key=get_last_modified)]
last_added = objs[-1].key

print(last_added)

global-jobs-storage
--->2019/../../..
--->recursive