code: def since(self, timestamp=None, version=None, deleted=False):
          
  
          qset = self
  
          if timestamp is not None:
  
              if isinstance(timestamp, numbers.Real):
                  timestamp = datetime.datetime.fromtimestamp(timestamp)
  
              qset = qset.filter(
                  models.Q(created__gt=timestamp) |
                  models.Q(updated__gt=timestamp)
              )
  
          if version is not None:
  
              qset = qset.filter(version__gt=version)
  
          if not deleted:
  
              qset = qset.undeleted()
  
          return qset
docs: Queries the database for objects updated since timestamp or version
  
          Arguments:
  
          timestamp <DateTime=None|int=None> if specified return all objects modified since
          that specified time. If integer is submitted it is treated like a unix timestamp
  
          version <int=None> if specified return all objects with a version greater
          then the one specified
  
          deleted <bool=False> if true include soft-deleted objects in the result
  
          Either timestamp or version needs to be provided