convert_utc_to_bct.py

# Convert a time in UTC to BTC
import pytz
from datetime import datetime
tz = pytz.timezone('UTC')
naive_time = datetime.strptime('2016-04-05 15:00', '%Y-%m-%d %H:%M')
tz_time = tz.localize(naive_time)
london_tz = pytz.timezone('Europe/London')
london_time = tz_time.astimezone(london_tz)

print(tz_time)
print(london_time)
# It prints out:
2016-04-05 15:00:00+00:00
2016-04-05 16:00:00+01:00

# Convert from BTC to UTC
import pytz
from datetime import datetime
tz = pytz.timezone('Europe/London')
naive_time = datetime.strptime('2016-04-05 16:00', '%Y-%m-%d %H:%M')
tz_time = tz.localize(naive_time)
utc_tz = pytz.timezone('UTC')
utc_time = tz_time.astimezone(utc_tz)

print(tz_time)
print(utc_time)
# It prints out:
2016-04-05 16:00:00+01:00
2016-04-05 15:00:00+00:00