diff --git a/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h b/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h
index bbb17ea8..1608e22a 100644
--- a/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h
+++ b/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h
@@ -21,6 +21,7 @@ typedef struct _mp_obj_Pbkdf2_t {
 STATIC mp_obj_t mod_TrezorCrypto_Pbkdf2_update(mp_obj_t self, mp_obj_t data);
 
 /// def trezor.crypto.pbkdf2(prf: str, password: bytes, salt: bytes, iterations: int=None) -> Pbkdf2:
+///     pass
 STATIC mp_obj_t mod_TrezorCrypto_Pbkdf2_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 3, 4, false);
     mp_obj_Pbkdf2_t *o = m_new_obj(mp_obj_Pbkdf2_t);
@@ -53,6 +54,7 @@ STATIC mp_obj_t mod_TrezorCrypto_Pbkdf2_make_new(const mp_obj_type_t *type, size
 }
 
 /// def trezor.crypto.pbkdf2.Pbkdf2.update(self, iterations: int) -> None:
+///     pass
 STATIC mp_obj_t mod_TrezorCrypto_Pbkdf2_update(mp_obj_t self, mp_obj_t iterations) {
     mp_obj_Pbkdf2_t *o = MP_OBJ_TO_PTR(self);
     uint32_t iter = mp_obj_get_int(iterations);
@@ -67,6 +69,7 @@ STATIC mp_obj_t mod_TrezorCrypto_Pbkdf2_update(mp_obj_t self, mp_obj_t iteration
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_TrezorCrypto_Pbkdf2_update_obj, mod_TrezorCrypto_Pbkdf2_update);
 
 /// def trezor.crypto.pbkdf2.Pbkdf2.key(self) -> bytes:
+///     pass
 STATIC mp_obj_t mod_TrezorCrypto_Pbkdf2_key(mp_obj_t self) {
     mp_obj_Pbkdf2_t *o = MP_OBJ_TO_PTR(self);
     vstr_t vstr;