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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def check_in_out_dates(self):
 """ When date_order is less then check-in date or Checkout date should be greater than the check-in date. """

        if self.checkout and self.checkin:
            if self.checkin < self.date_order:
                raise ValidationError(_('Check-in date should be greater than \
                                         the current date.'))
            if self.checkout < self.checkin:
                raise ValidationError(_('Check-out date should be greater \
                                         than Check-in date.'))