*.py
###Part One
from datetime import date, datetime, timedelta, time
from time import time
import time
import calendar

###Part Two
#Count Date
hire_date = fields.Date(string="Hire Date", default=fields.Date.today)
count_start = fields.Date(string="Count Start", default=fields.Date.today, store=True, compute='_get_count_start', inverse='_write_count_start')
count_end = fields.Date(string="Count End", default=fields.Date.today, store=True, compute='_get_count_end', inverse='_write_count_end')
resign_date = fields.Date(string="Resign Date", default="3000-12-31")
#Count Date

###Part Three
#Count Date
@api.onchange('hire_date')
def _get_count_start(self):
for hr_employee_id in self:
if hr_employee_id.hire_date > hr_employee_id.count_start:
hr_employee_id.count_start = hr_employee_id.hire_date

def _write_count_start(self):
for hr_employee_id in self:
if hr_employee_id.hire_date > hr_employee_id.count_start:
hr_employee_id.count_start = hr_employee_id.hire_date

@api.onchange('resign_date')
def _get_count_end(self):
for hr_employee_id in self:
if hr_employee_id.resign_date < hr_employee_id.count_end:
hr_employee_id.count_end = hr_employee_id.resign_date+timedelta(-1)

def _write_count_end(self):
for hr_employee_id in self:
if hr_employee_id.resign_date < hr_employee_id.count_end:
hr_employee_id.count_end = hr_employee_id.resign_date+timedelta(-1)
#Count Date