diff --git a/README.md b/README.md
index 75948f1..e2adac6 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,13 @@ pyenv local 3.9.13
 poetry install
 ```
 
+### Configuration
+```bash
+mv .env.example .env
+# edit .env file
+vim .env
+```
+
 ## Run mint
 ```bash
 poetry run uvicorn mint.app:app --port 3338
diff --git a/mint/app.py b/mint/app.py
index 7171267..da0189d 100644
--- a/mint/app.py
+++ b/mint/app.py
@@ -1,13 +1,10 @@
 import asyncio
 import logging
 import sys
-from ast import Param
 from typing import Union
 
 from ecc.curve import Point, secp256k1
 from fastapi import FastAPI
-from fastapi.params import Body, Depends, Query
-from fastapi.routing import APIRouter
 from loguru import logger
 
 import core.settings as settings
diff --git a/mint/ledger.py b/mint/ledger.py
index 4fcd55a..f4027c7 100644
--- a/mint/ledger.py
+++ b/mint/ledger.py
@@ -3,7 +3,6 @@ Implementation of https://gist.github.com/phyro/935badc682057f418842c72961cf096c
 """
 
 import hashlib
-import time
 
 from ecc.curve import Point, secp256k1
 from ecc.key import gen_keypair
@@ -14,9 +13,14 @@ from core.db import Database
 from core.settings import MAX_ORDER
 from core.split import amount_split
 from lightning import WALLET
-from mint.crud import (get_lightning_invoice, get_proofs_used,
-                       invalidate_proof, store_lightning_invoice,
-                       store_promise, update_lightning_invoice)
+from mint.crud import (
+    get_lightning_invoice,
+    get_proofs_used,
+    invalidate_proof,
+    store_lightning_invoice,
+    store_promise,
+    update_lightning_invoice,
+)
 
 
 class Ledger:
diff --git a/wallet/wallet.py b/wallet/wallet.py
index 70bdd51..311abdb 100644
--- a/wallet/wallet.py
+++ b/wallet/wallet.py
@@ -1,4 +1,3 @@
-import asyncio
 import random
 from typing import List