diff --git a/blockchain/miner.py b/blockchain/miner.py
index 2a0a17daf..024156d65 100644
--- a/blockchain/miner.py
+++ b/blockchain/miner.py
@@ -1,6 +1,8 @@
 import time
+
 from blockchain.block import Blockchain
 
+
 class Miner:
     def __init__(self, blockchain):
         self.blockchain = blockchain
@@ -9,12 +11,12 @@ def mine_block(self, data):
         while True:
             if self.blockchain.is_chain_valid(self.blockchain.chain):
                 self.blockchain.add_block(data)
-                print('Block successfully mined!')
-                print('Proof of work: {}'.format(self.blockchain.chain[-1].hash))
+                print("Block successfully mined!")
+                print("Proof of work: {}".format(self.blockchain.chain[-1].hash))
                 break
             else:
-                print('Block not mined. Invalid chain.')
+                print("Block not mined. Invalid chain.")
                 self.blockchain.chain = [self.blockchain.create_genesis_block()]
                 self.blockchain.difficulty += 1
-                print('New difficulty: {}'.format(self.blockchain.difficulty))
+                print("New difficulty: {}".format(self.blockchain.difficulty))
                 time.sleep(1)