style: format code with Autopep8, Black, ClangFormat, dotnet-format, …

…Go fmt, Gofumpt, Google Java Format, isort, Ktlint, PHP CS Fixer, Prettier, RuboCop, Ruff Formatter, Rustfmt, Scalafmt, StandardJS, StandardRB, swift-format and Yapf

This commit fixes the style issues introduced in 9ba40d4 according to the output
from Autopep8, Black, ClangFormat, dotnet-format, Go fmt, Gofumpt, Google Java
Format, isort, Ktlint, PHP CS Fixer, Prettier, RuboCop, Ruff Formatter, Rustfmt,
Scalafmt, StandardJS, StandardRB, swift-format and Yapf.

Details: None

blockchain/blockchain.py

@@ -1,6 +1,7 @@
 import hashlib
 import time
 
+
 class Block:
     def __init__(self, index, previous_hash, timestamp, data, hash):
         self.index = index
@@ -9,29 +10,43 @@ def __init__(self, index, previous_hash, timestamp, data, hash):
         self.data = data
         self.hash = hash
 
+
 class Blockchain:
     def __init__(self):
         self.chain = [self.create_genesis_block()]
         self.difficulty = 5
 
     def create_genesis_block(self):
-        return Block(0, "0" * 64, int(time.time()), "Genesis Block", self.calculate_hash(0, "0" * 64, int(time.time()), "Genesis Block"))
+        return Block(
+            0,
+            "0" * 64,
+            int(time.time()),
+            "Genesis Block",
+            self.calculate_hash(0, "0" * 64, int(time.time()), "Genesis Block"),
+        )
 
     def calculate_hash(self, index, previous_hash, timestamp, data):
         value = str(index) + str(previous_hash) + str(timestamp) + str(data)
-        return hashlib.sha256(value.encode('utf-8')).hexdigest()
+        return hashlib.sha256(value.encode("utf-8")).hexdigest()
 
     def add_block(self, block):
         block.previous_hash = self.chain[-1].hash
-        block.hash = self.calculate_hash(block.index, block.previous_hash, block.timestamp, block.data)
+        block.hash = self.calculate_hash(
+            block.index, block.previous_hash, block.timestamp, block.data
+        )
         self.chain.append(block)
 
     def is_valid(self):
         for i in range(1, len(self.chain)):
             current_block = self.chain[i]
             previous_block = self.chain[i - 1]
 
-            if current_block.hash != self.calculate_hash(current_block.index, current_block.previous_hash, current_block.timestamp, current_block.data):
+            if current_block.hash != self.calculate_hash(
+                current_block.index,
+                current_block.previous_hash,
+                current_block.timestamp,
+                current_block.data,
+            ):
                 return False
 
             if previous_block.hash != current_block.previous_hash: