2 files changed, 2 insertions, 2 deletions
diff --git a/Modules/_blake2/blake2b_impl.c b/Modules/_blake2/blake2b_impl.c
index 5d108ed..8b0d60d 100644
--- a/Modules/_blake2/blake2b_impl.c
+++ b/Modules/_blake2/blake2b_impl.c
@@ -409,6 +409,6 @@ static PyType_Slot blake2b_type_slots[] = {
 PyType_Spec blake2b_type_spec = {
     .name = "_blake2.blake2b",
     .basicsize =  sizeof(BLAKE2bObject),
-    .flags = Py_TPFLAGS_DEFAULT,
+    .flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE,
     .slots = blake2b_type_slots
 };
diff --git a/Modules/_blake2/blake2s_impl.c b/Modules/_blake2/blake2s_impl.c
index 85c2d4e..7ab3917 100644
--- a/Modules/_blake2/blake2s_impl.c
+++ b/Modules/_blake2/blake2s_impl.c
@@ -408,6 +408,6 @@ static PyType_Slot blake2s_type_slots[] = {
 PyType_Spec blake2s_type_spec = {
     .name = "_blake2.blake2s",
     .basicsize =  sizeof(BLAKE2sObject),
-    .flags = Py_TPFLAGS_DEFAULT,
+    .flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_IMMUTABLETYPE,
     .slots = blake2s_type_slots
 };