code: def timesince_or_never(dt, default=None):
      
      if default is None:
          default = _("Never")
  
      if isinstance(dt, datetime.date):
          return timesince(dt)
      else:
          return default
docs: Call the Django ``timesince`` filter or a given default string.
  
      It returns the string *default* if *dt* is not a valid ``date``
      or ``datetime`` object.
      When *default* is None, "Never" is returned.