code: def doc_id(self):
          
          if self.id:
              return '%s_%s' % (self.doc_type, self.id.lower())
          return self._hashed_key
docs: Returns the couchbase document's id, object property.
  
          :returns: The document id (that is created from :attr:'doc_type' and
              :attr:'__key_field__' value, or auto-hashed document id at first
              saving).
          :rtype: unicode