day_range.py

import pendulum


date_period = pendulum.period(
    pendulum.datetime(2019, 1, 1),
    pendulum.datetime(2019, 3, 20),
)

for dt in date_period.range("days"):
    start, end = dt.start_of("day"), dt.end_of("end")
    print(start, end)

# 2019-02-16T00:00:00+00:00 2019-02-16T23:59:59.999999+00:00
# 2019-02-17T00:00:00+00:00 2019-02-17T23:59:59.999999+00:00
# 2019-02-18T00:00:00+00:00 2019-02-18T23:59:59.999999+00:00
# 2019-02-19T00:00:00+00:00 2019-02-19T23:59:59.999999+00:00
# 2019-02-20T00:00:00+00:00 2019-02-20T23:59:59.999999+00:00