diff --git a/pytential/symbolic/execution.py b/pytential/symbolic/execution.py
index dd7168668..0984bf0d8 100644
--- a/pytential/symbolic/execution.py
+++ b/pytential/symbolic/execution.py
@@ -919,10 +919,10 @@ def merge(self, places):
         return self.copy(places=new_places)
 
     def __repr__(self):
-        return "{type(self).__name__}({repr(self.places)})"
+        return f"{type(self).__name__}({repr(self.places)})"
 
     def __str__(self):
-        return "{type(self).__name__}({repr(self.places)})"
+        return f"{type(self).__name__}({repr(self.places)})"
 
 # }}}