'Update the number_of_days.'

@api.onchange('date_to')
def _onchange_date_to(self):

    date_from = self.date_from
    date_to = self.date_to
    if ((date_to and date_from) and (date_from <= date_to)):
        self.number_of_days_temp = self._get_number_of_days(date_from, date_to, self.employee_id.id)
    else:
        self.number_of_days_temp = 0
