1 files changed, 30 insertions, 21 deletions
diff --git a/docs/development/custom-vectors/arc4/generate_arc4.py b/docs/development/custom-vectors/arc4/generate_arc4.py
index 3dee44a30..2ca85c98d 100644
--- a/docs/development/custom-vectors/arc4/generate_arc4.py
+++ b/docs/development/custom-vectors/arc4/generate_arc4.py
@@ -12,10 +12,14 @@ from cryptography.hazmat.primitives.ciphers import algorithms
 
 
 _RFC6229_KEY_MATERIALS = [
-    (True,
-     8 * '0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20'),
-    (False,
-     8 * '1ada31d5cf688221c109163908ebe51debb46227c6cc8b37641910833222772a')
+    (
+        True,
+        8 * "0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20",
+    ),
+    (
+        False,
+        8 * "1ada31d5cf688221c109163908ebe51debb46227c6cc8b37641910833222772a",
+    ),
 ]
 
 
@@ -37,42 +41,43 @@ _RFC6229_OFFSETS = [
     3056,
     3072,
     4080,
-    4096
+    4096,
 ]
 
 
-_SIZES_TO_GENERATE = [
-    160
-]
+_SIZES_TO_GENERATE = [160]
 
 
 def _key_for_size(size, keyinfo):
     msb, key = keyinfo
     if msb:
-        return key[:size // 4]
+        return key[: size // 4]
     else:
-        return key[-size // 4:]
+        return key[-size // 4 :]
 
 
 def _build_vectors():
     count = 0
     output = []
     key = None
-    plaintext = binascii.unhexlify(32 * '0')
+    plaintext = binascii.unhexlify(32 * "0")
     for size in _SIZES_TO_GENERATE:
         for keyinfo in _RFC6229_KEY_MATERIALS:
             key = _key_for_size(size, keyinfo)
             cipher = ciphers.Cipher(
                 algorithms.ARC4(binascii.unhexlify(key)),
                 None,
-                default_backend())
+                default_backend(),
+            )
             encryptor = cipher.encryptor()
             current_offset = 0
             for offset in _RFC6229_OFFSETS:
                 if offset % 16 != 0:
                     raise ValueError(
-                        "Offset {} is not evenly divisible by 16"
-                        .format(offset))
+                        "Offset {} is not evenly divisible by 16".format(
+                            offset
+                        )
+                    )
                 while current_offset < offset:
                     encryptor.update(plaintext)
                     current_offset += len(plaintext)
@@ -80,19 +85,23 @@ def _build_vectors():
                 count += 1
                 output.append("KEY = {}".format(key))
                 output.append("OFFSET = {}".format(offset))
-                output.append("PLAINTEXT = {}".format(
-                    binascii.hexlify(plaintext)))
-                output.append("CIPHERTEXT = {}".format(
-                    binascii.hexlify(encryptor.update(plaintext))))
+                output.append(
+                    "PLAINTEXT = {}".format(binascii.hexlify(plaintext))
+                )
+                output.append(
+                    "CIPHERTEXT = {}".format(
+                        binascii.hexlify(encryptor.update(plaintext))
+                    )
+                )
                 current_offset += len(plaintext)
             assert not encryptor.finalize()
     return "\n".join(output)
 
 
 def _write_file(data, filename):
-    with open(filename, 'w') as f:
+    with open(filename, "w") as f:
         f.write(data)
 
 
-if __name__ == '__main__':
-    _write_file(_build_vectors(), 'arc4.txt')
+if __name__ == "__main__":
+    _write_file(_build_vectors(), "arc4.txt")