text: from django.db import models
  
  class Bike(models.Model):
      start=models.DateField(auto_now=False, auto_now_add=True)
      type=models.CharField(max_length=20)
      price=models.DecimalField( max_digits=8, decimal_places=2)
  
      def __str__(self):
          return "Bike id:%s, start:%s type:%s price:%s"\
              %(self.id,self.start,self.type,self.price)
  
      def get_absolute_url(self):
          from django.urls import reverse
          return reverse('bike', args=[str(self.id)])