diff --git a/slhdsa/lowlevel/slhdsa.py b/slhdsa/lowlevel/slhdsa.py
index f5c092d..ebb2578 100644
--- a/slhdsa/lowlevel/slhdsa.py
+++ b/slhdsa/lowlevel/slhdsa.py
@@ -19,7 +19,7 @@ def keygen(par: Parameter) -> tuple[tuple[bytes, bytes, bytes, bytes], tuple[byt
 
 def validate_secretkey(secret_key: tuple[bytes, bytes, bytes, bytes], par: Parameter) -> bool:
     sk_seed, sk_prf, pk_seed, pk_root = secret_key
-    # len(sk_prf)  # magic patch for mypyc, otherwise mypyc will crash
+    len(sk_prf)  # magic patch for mypyc, otherwise mypyc will crash
     address = Address(par.d - 1, 0, 0)
     pk_root_new = XMSS(par).node(sk_seed, 0, par.h_m, pk_seed, address)
     return pk_root == pk_root_new
diff --git a/slhdsa/slhdsa.py b/slhdsa/slhdsa.py
index 6bbcd40..a4ec52d 100644
--- a/slhdsa/slhdsa.py
+++ b/slhdsa/slhdsa.py
@@ -25,7 +25,7 @@ def from_digest(cls, digest: bytes, par: Parameter) -> "PublicKey":
             raise exc.SLHDSAKeyException('Wrong digest length')
         return cls((digest[:par.n], digest[par.n:]), par)
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f'<SLHDSA Public Key: {self.digest().hex()}>'
 
 
@@ -55,7 +55,7 @@ def from_digest(cls, digest: bytes, par: Parameter) -> "SecretKey":
             raise exc.SLHDSAKeyException("Wrong digest length")
         return cls((digest[:par.n], digest[par.n:par.n*2], digest[par.n*2:par.n*3], digest[par.n*3:]), par)
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f'<SLHDSA Secret Key: {self.digest().hex()}>'