import datetime
start = '2020-01-01'
end = '2020-12-31'
datestart = datetime.datetime.strptime(start, '%Y-%m-%d')
dateend = datetime.datetime.strptime(end, '%Y-%m-%d')
while datestart < dateend:
datestart += datetime.timedelta(days=1)
print(datestart.strftime('%Y%m%d'))