old_contents: from django.db import models
  from django.db.models.deletion import PROTECT
  from django_extensions.db.fields import AutoSlugField
  
  
  class Workshop(models.Model):
      event = models.ForeignKey('events.Event', PROTECT, related_name='workshops')
      applicant = models.ForeignKey('cfp.Applicant', related_name='workshops')
  
      title = models.CharField(max_length=80)
      slug = AutoSlugField(populate_from="title", unique=True)
      about = models.TextField()
      abstract = models.TextField()
      extra_info = models.TextField(blank=True)
      skill_level = models.ForeignKey('cfp.AudienceSkillLevel', PROTECT)
      starts_at = models.DateTimeField()
      duration_hours = models.DecimalField(max_digits=3, decimal_places=1)
      tickets_link = models.URLField(blank=True)
      price = models.PositiveIntegerField(blank=True, null=True)
  
      @property
      def approximate_euro_price(self):
          return int(self.price / 7.5)
  
new_contents: from django.db import models
  from django.db.models.deletion import PROTECT
  from django_extensions.db.fields import AutoSlugField
  
  
  class Workshop(models.Model):
      event = models.ForeignKey('events.Event', PROTECT, related_name='workshops')
      applicant = models.ForeignKey('cfp.Applicant', related_name='workshops')
  
      title = models.CharField(max_length=80)
      slug = AutoSlugField(populate_from="title", unique=True)
      about = models.TextField()
      abstract = models.TextField()
      extra_info = models.TextField(blank=True)
      skill_level = models.ForeignKey('cfp.AudienceSkillLevel', PROTECT)
      starts_at = models.DateTimeField()
      duration_hours = models.DecimalField(max_digits=3, decimal_places=1)
      tickets_link = models.URLField(blank=True)
      price = models.PositiveIntegerField(blank=True, null=True)
  
      @property
      def approximate_euro_price(self):
          return int(self.price / 7.5) if self.price else None
  
subject: Check price exists before using it