use get_values instead of iter_values

Co-authored-by: Joren Dumoulin <[email protected]>

xdsl/dialects/cf.py

@@ -239,7 +239,7 @@ def case_operand(self) -> tuple[VarOperand, ...]:
 
         def_sizes = cast(
             tuple[int, ...],
-            tuple(size for size in self.case_operand_segments.iter_values()),
+            self.case_operand_segments.get_values(),
         )
 
         if sum(def_sizes) != len(self.case_operands):