name = self._ssa_name('cst')
    cst_ty = _get_type_from_proto(None, attr_def)
    try:
      cst_val = _get_val_from_proto(cst_ty, attr_def.default_value)
    except AttributeError:
      raise AttributeError(
          f'attribute "{attr_def.name}" does not have default_value. If the '
          "attribute names from the API and OpDef don't match, please add it "
          'to _ATTRIBUTE_RENAMES.')