code: def _validate_filters_ndb(cls, filters, model_class):
      
      if not filters:
        return
  
      properties = model_class._properties
  
      for f in filters:
        prop, _, val = f
        if prop not in properties:
          raise errors.BadReaderParamsError(
              "Property %s is not defined for entity type %s",
              prop, model_class._get_kind())
  
        # Validate the value of each filter. We need to know filters have
        # valid value to carry out splits.
        try:
          properties[prop]._do_validate(val)
        except db.BadValueError, e:
          raise errors.BadReaderParamsError(e)
docs: Validate ndb.Model filters.