Update packages/bigframes/bigframes/operations/strings.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: shuoweil

packages/bigframes/bigframes/operations/strings.py

@@ -313,7 +313,7 @@ def _to_blob(self, connection: Optional[str] = None) -> T:
         ):
             session = self._data._block.session
         else:
-            raise ValueError("to_blob is only supported via Series.str")
+            raise ValueError(f"{self._to_blob.__name__} is only supported via Series.str")
         connection = session._create_bq_connection(connection=connection)
         return self._data._apply_binary_op(connection, ops.obj_make_ref_op)