chore: fix formatting and add type hints

Author: mapaba79

blockchain/simple_proof_of_work.py

@@ -1,18 +1,20 @@
 import hashlib
 
-def proof_of_work(block_number: int, transactions: str, previous_hash: str, 
-                  difficulty: int) -> tuple[int, str]:
+
+def proof_of_work(
+    block_number: int, transactions: str, previous_hash: str, difficulty: int
+) -> tuple[int, str]:
     """
-    Finds a nonce such that the hash of the block 
-    starts with a specfic number of zeros
+    Finds a nonce such that the hash of the block
+    starts with a specific number of zeros
     """
-    prefix = '0' * difficulty
+    prefix = "0" * difficulty
     nonce = 0
 
     while True:
         # Create a single string representing all block data
         text = str(block_number) + transactions + previous_hash + str(nonce)
-        
+
         # Calculate the SHA-256
         current_hash = hashlib.sha256(text.encode()).hexdigest()
 
@@ -22,14 +24,15 @@ def proof_of_work(block_number: int, transactions: str, previous_hash: str,
 
         nonce += 1
 
+
 if __name__ == "__main__":
     # Example usage:
     example_tx = "Alice sends 1 BTC to Bob"
     prev_h = "00000abcdef1234567890"
-    diff = 5 # Increase to see get much slower
+    diff = 5  # Increase to see get much slower
 
     print(f"Mining block... (Difficulty: {diff})")
-    nonce,hash_found = proof_of_work(1, example_tx, prev_h, diff)
+    nonce, hash_found = proof_of_work(1, example_tx, prev_h, diff)
 
     print(f"Success! Nonce: {nonce}")
     print(f"Hash: {hash_found}")