import re

from datetime import datetime, timezone, timedelta

def to_timestamp(dt_str, tz_str):

    rec = re.compile(r'^(UTC)([\+\-])(0[0-9]|1[0-9]|2[0-3]|[0-9])\:00$')

    dt = datetime.strptime(dt_str,'%Y-%m-%d %H:%M:%S')

    tz_1 = rec.match(tz_str).group(2)

    tz_2 = rec.match(tz_str).group(3)

    zone = int(tz_1 + tz_2)

    tz_utc = timezone(timedelta(hours = zone))

    dt_time = dt.replace(tzinfo = tz_utc)

    return dt_time.timestamp()

# 测试:

t1 = to_timestamp('2015-6-1 08:10:30', 'UTC+7:00')

print(t1)

assert t1 == 1433121030.0, t1

t2 = to_timestamp('2015-5-31 16:10:30', 'UTC-09:00')

print(t2)

assert t2 == 1433121030.0, t2

print('ok')