from django.db import models
from django.core.validators import MinValueValidator, \
                                   MaxValueValidator
class Coupon(models.Model):
    code = models.CharField(max_length=50, 
                            unique=True) 
    valid_from = models.DateTimeField() 
    valid_to = models.DateTimeField() 
    discount = models.IntegerField(
                   validators=[MinValueValidator(0), 
                               MaxValueValidator(100)], 
                   help_text='Wartość procentowa (od 0 do 100) ') 
    active = models.BooleanField()
    def __str__(self): 
        return self.code 