old_contents: from django.contrib.gis.db import models
  from django.contrib.gis import geos
  from datetime import datetime
  
  class Venue(models.Model):
      name = models.CharField(max_length=255)
      street_address = models.TextField() 
      country = models.CharField(max_length=255)
      location = models.PointField(blank=True)
  
      objects = models.GeoManager()
  
      def __init__(self, *args, **kwargs):
          super(Venue, self).__init__(*args, **kwargs)
          if self.location is None:
              self.location = geos.Point(0, 0)
  
      @property
      def latitude(self):
          return self.location.x
      
      @latitude.setter
      def latitude(self, value):
          self.location.x = value
  
      @property
      def longitude(self):
          return self.location.y
  
      @longitude.setter
      def longitude(self, value):
          self.location.y = value
  
  class Event(models.Model):
      name = models.CharField(max_length=255)
      event_url = models.CharField(max_length=255, blank = True)
      venue = models.ForeignKey(Venue)
      start = models.DateTimeField(null = True, blank = True)
      end = models.DateTimeField(null = True, blank = True)
      source_id = models.CharField(max_length=255)
      organiser_email = models.CharField(max_length=255)
  
      objects = models.GeoManager()
  
      @classmethod
      def upcoming(self):
          return self.objects.filter(start__gte = datetime.now())
  
new_contents: from django.contrib.gis.db import models
  from django.contrib.gis import geos
  from datetime import datetime
  
  class Venue(models.Model):
      name = models.CharField(max_length=255)
      street_address = models.TextField() 
      country = models.CharField(max_length=255)
      location = models.PointField(blank=True)
  
      objects = models.GeoManager()
  
      def __init__(self, *args, **kwargs):
          super(Venue, self).__init__(*args, **kwargs)
          if self.location is None:
              self.location = geos.Point(0, 0)
  
      @property
      def latitude(self):
          return self.location.x
      
      @latitude.setter
      def latitude(self, value):
          self.location.x = value
  
      @property
      def longitude(self):
          return self.location.y
  
      @longitude.setter
      def longitude(self, value):
          self.location.y = value
  
  class Event(models.Model):
      name = models.CharField(max_length = 255)
      event_url = models.CharField(max_length = 255, blank = True)
      venue = models.ForeignKey(Venue)
      start = models.DateTimeField(null = True, blank = True)
      end = models.DateTimeField(null = True, blank = True)
      source_id = models.CharField(max_length = 255, blank = True)
      organiser_email = models.CharField(max_length = 255)
  
      objects = models.GeoManager()
  
      @classmethod
      def upcoming(self):
          return self.objects.filter(start__gte = datetime.now())
  
subject: Allow blank source_id in event, tweak formatting of the code