Python string to timestamp

timestamp.py

import datetime
import time

def from_string_to_timestamp(st):
    if st.find('-') != -1:
        splitted = st.split('-')
    else:
        splitted = st.split('.')

    try:
        day = int(splitted[0])
        month = int(splitted[1])
        year = int(splitted[2])
    except IndexError:
        raise FormatError()

    dt = datetime.datetime(year, month, day)

    if year < 1970:
        epoch = datetime.datetime(1970, 1, 1)
        diff = dt-epoch
        timestamp = diff.days * 24 * 3600 + diff.seconds
    else:
        timestamp = time.mktime(dt.timetuple())
        timestamp = int(timestamp)

    MAGIC_NUMBER = 25200 # Adds 8 hours
    return timestamp + MAGIC_NUMBER


class FormatError(Exception): 
    pass