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 73b629b 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

tests/test_transaction.py

@@ -1,18 +1,22 @@
 import unittest
+
 from transaction import Transaction
 
+
 class TestTransaction(unittest.TestCase):
     def test_create_transaction(self):
         transaction = Transaction("sender", "receiver", 100)
         self.assertEqual(transaction.sender, "sender")
         self.assertEqual(transaction.receiver, "receiver")
         self.assertEqual(transaction.amount, 100)
         self.assertEqual(transaction.timestamp, 1234567890)
-        self.assertEqual(transaction.hash, "hash_value")  # Replace with actual hash value
+        # Replace with actual hash value
+        self.assertEqual(transaction.hash, "hash_value")
 
     def test_calculate_hash(self):
         transaction = Transaction("sender", "receiver", 100)
-        self.assertEqual(transaction.calculate_hash(), "hash_value")  # Replace with actual hash value
+        # Replace with actual hash value
+        self.assertEqual(transaction.calculate_hash(), "hash_value")
 
     def test_is_valid(self):
         transaction = Transaction("sender", "receiver", 100)