from datetime import time

seconds_in_one_hour = 3600
earliest_start_time_for_nightshift = time(18,0)
latest_start_time_for_nightshift = time(2,0)
work_time_limit_for_pregnant_in_hours = 12
limit_for_working_days_in_a_row = 12
number_of_days_working_nightshift = 3
number_of_days_rest_after_nightshift = 3