diff --git a/cashu/mint/crud.py b/cashu/mint/crud.py
index 18a7195..a608967 100644
--- a/cashu/mint/crud.py
+++ b/cashu/mint/crud.py
@@ -93,7 +93,7 @@ async def get_lightning_invoice(
         SELECT * from invoices
         WHERE hash = ?
         """,
-        hash,
+        (hash,),
     )
     return Invoice.from_row(row)
 
@@ -106,5 +106,8 @@ async def update_lightning_invoice(
 ):
     await (conn or db).execute(
         "UPDATE invoices SET issued = ? WHERE hash = ?",
-        (issued, hash),
+        (
+            issued,
+            hash,
+        ),
     )
diff --git a/cashu/mint/ledger.py b/cashu/mint/ledger.py
index 9b94261..522e54d 100644
--- a/cashu/mint/ledger.py
+++ b/cashu/mint/ledger.py
@@ -30,9 +30,9 @@ class Ledger:
     def __init__(self, secret_key: str, db: str):
         self.proofs_used: Set[str] = set()
 
-        self.master_key: str = secret_key
-        self.keys: List[PrivateKey] = self._derive_keys(self.master_key)
-        self.pub_keys: List[PublicKey] = self._derive_pubkeys(self.keys)
+        self.master_key = secret_key
+        self.keys = self._derive_keys(self.master_key)
+        self.pub_keys = self._derive_pubkeys(self.keys)
         self.db: Database = Database("mint", db)
 
     async def load_used_proofs(self):
diff --git a/cashu/wallet/crud.py b/cashu/wallet/crud.py
index 95dc464..bacb968 100644
--- a/cashu/wallet/crud.py
+++ b/cashu/wallet/crud.py
@@ -1,5 +1,5 @@
 import time
-from typing import Optional, List
+from typing import Optional, List, Any
 
 from cashu.core.base import Proof, P2SHScript
 from cashu.core.db import Connection, Database
@@ -59,7 +59,7 @@ async def invalidate_proof(
         DELETE FROM proofs
         WHERE secret = ?
         """,
-        str(proof["secret"]),
+        (str(proof["secret"]),),
     )
 
     await (conn or db).execute(
@@ -80,7 +80,7 @@ async def update_proof_reserved(
     conn: Optional[Connection] = None,
 ):
     clauses = []
-    values = []
+    values: List[Any] = []
     clauses.append("reserved = ?")
     values.append(reserved)
 
@@ -110,7 +110,7 @@ async def secret_used(
         SELECT * from proofs
         WHERE secret = ?
         """,
-        (secret),
+        (secret,),
     )
     return rows is not None
 
@@ -127,7 +127,12 @@ async def store_p2sh(
           (address, script, signature, used)
         VALUES (?, ?, ?, ?)
         """,
-        (p2sh.address, p2sh.script, p2sh.signature, False),
+        (
+            p2sh.address,
+            p2sh.script,
+            p2sh.signature,
+            False,
+        ),
     )