timestamp to datetime. Timezone aware vs. nieve

tz.py

import datetime

def process_ts(ts, callback):
    st = callback(ts)
    print(st)

def run():

    def do_no_tz(ts):
        return datetime.datetime.utcfromtimestamp(ts)
        #return res.strftime("%m/%d/%Y, %H:%M:%S")

    def do_strftime(ts):
        res = datetime.datetime.utcfromtimestamp(ts)
        return res.strftime('%b %d %Y')

    print("Show nieve dt is bad")
    process_ts(1609477200, do_no_tz) # Jan 1, 2021 0:00:00
    process_ts(1609560000, do_no_tz) # Jan 1, 2021 23:00:00

    print("Show https://bitbucket.org/raviolilabs/main-site/src/5bea64294ece439897d92aae3afd71a339d4c0bb/metrics/lib/CommitVolumeByPullRequest.py#lines-53")
    process_ts(1609477200, do_strftime) # Jan 1, 2021 0:00:00
    process_ts(1609560000, do_strftime) # Jan 1, 2021 23:00:00
    
run()