fix format string lint detected by flake8 5.0.3

1 files changed, 2 insertions, 2 deletions

diff --git a/dns/renderer.py b/dns/renderer.py
index 63fb3fa..3c495f6 100644
--- a/dns/renderer.py
+++ b/dns/renderer.py
@@ -313,9 +313,9 @@ class Renderer:
     def reserve(self, size: int) -> None:
         """Reserve *size* bytes."""
         if size < 0:
-            raise ValueError(f"reserved amount must be non-negative")
+            raise ValueError("reserved amount must be non-negative")
         if size > self.max_size:
-            raise ValueError(f"cannot reserve more than the maximum size")
+            raise ValueError("cannot reserve more than the maximum size")
         self.reserved += size
         self.max_size -= size