diff --git a/scripts/mbedtls_dev/bignum_mod_raw.py b/scripts/mbedtls_dev/bignum_mod_raw.py
index 98605d655..89ae825fc 100644
--- a/scripts/mbedtls_dev/bignum_mod_raw.py
+++ b/scripts/mbedtls_dev/bignum_mod_raw.py
@@ -118,7 +118,7 @@ class BignumModRawConvertRep(bignum_common.ModOperationCommon,
     arity = 1
     rep = bignum_common.ModulusRepresentation.INVALID
 
-    def set_representation(self, r: bignum_common.ModulusRepresentation) -> bool:
+    def set_representation(self, r: bignum_common.ModulusRepresentation) -> None:
         self.rep = r
 
     def arguments(self) -> List[str]: