[pre-commit.ci] auto fixes from pre-commit.com hooks

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Author: pre-commit-ci[bot]

blockchain/pow_algorithm.py

@@ -2,15 +2,16 @@
 # Title: Proof of Work Algorithm for Blockchain
 
 ## Algorithm Statement:
-The algorithm implements the Proof of Work (PoW) consensus mechanism used in 
-blockchain to validate blocks. PoW ensures participants (miners) perform a 
-computational task to create a valid block and add it to the blockchain. The 
+The algorithm implements the Proof of Work (PoW) consensus mechanism used in
+blockchain to validate blocks. PoW ensures participants (miners) perform a
+computational task to create a valid block and add it to the blockchain. The
 difficulty is defined by the number of leading zeros required in the block hash.
 """
 
 import hashlib
 import time
 
+
 class Block:
     def __init__(self, index, previous_hash, transactions, timestamp, difficulty):
         self.index = index
@@ -36,16 +37,19 @@ def compute_hash(self):
     def mine_block(self):
         """
         Performs Proof of Work by adjusting the nonce until a valid hash is found.
-        A valid hash has the required number of leading zeros based on the difficulty 
+        A valid hash has the required number of leading zeros based on the difficulty
         level.
         """
-        target = '0' * self.difficulty  # Target hash should start with 'difficulty' zeros
-        while self.hash[:self.difficulty] != target:
+        target = (
+            "0" * self.difficulty
+        )  # Target hash should start with 'difficulty' zeros
+        while self.hash[: self.difficulty] != target:
             self.nonce += 1
             self.hash = self.compute_hash()
 
         print(f"Block mined with nonce {self.nonce}, hash: {self.hash}")
 
+
 class Blockchain:
     def __init__(self, difficulty):
         self.chain = []
@@ -65,14 +69,19 @@ def add_block(self, transactions):
         Adds a new block to the blockchain after performing Proof of Work.
         """
         previous_block = self.chain[-1]
-        new_block = Block(len(self.chain), previous_block.hash, transactions, time.time(), 
-                          self.difficulty)
+        new_block = Block(
+            len(self.chain),
+            previous_block.hash,
+            transactions,
+            time.time(),
+            self.difficulty,
+        )
         new_block.mine_block()
         self.chain.append(new_block)
 
     def is_chain_valid(self):
         """
-        Verifies the integrity of the blockchain by ensuring each block's previous 
+        Verifies the integrity of the blockchain by ensuring each block's previous
         hash matches and that all blocks meet the Proof of Work requirement.
         """
         for i in range(1, len(self.chain)):
@@ -89,8 +98,10 @@ def is_chain_valid(self):
 
         return True
 
+
 # Test cases
 
+
 def test_blockchain():
     """
     Test cases for the Blockchain proof of work algorithm.
@@ -106,11 +117,16 @@ def test_blockchain():
     assert blockchain.is_chain_valid(), "Blockchain should be valid"
 
     # Tamper with the blockchain and check validation
-    blockchain.chain[1].transactions = "Transaction 1: Alice pays Bob 50 BTC"  # Tampering
-    assert not blockchain.is_chain_valid(), "Blockchain should be invalid due to tampering"
+    blockchain.chain[
+        1
+    ].transactions = "Transaction 1: Alice pays Bob 50 BTC"  # Tampering
+    assert (
+        not blockchain.is_chain_valid()
+    ), "Blockchain should be invalid due to tampering"
 
     print("All test cases passed.")
 
+
 if __name__ == "__main__":
     test_blockchain()