slip39: Fix style.

src/trezor/crypto/slip39.py

@@ -18,14 +18,13 @@
 # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #
 
-from trezor.crypto import pbkdf2
-from trezor.crypto import hmac
-from trezor.crypto import hashlib
 import math
+
+from trezor.crypto import hashlib, hmac, pbkdf2, random
 from trezor.crypto.slip39_wordlist import wordlist
-from trezor.crypto import random
 from trezorcrypto import shamir
 
+
 class ConfigurationError(Exception):
     pass
 
@@ -150,9 +149,7 @@ class ShamirMnemonic(object):
     def _int_to_indices(value, length, bits):
         """Converts an integer value to indices in big endian order."""
         mask = (1 << bits) - 1
-        return (
-            (value >> (i * bits)) & mask for i in reversed(range(length))
-        )
+        return ((value >> (i * bits)) & mask for i in reversed(range(length)))
 
     def mnemonic_from_indices(self, indices):
         return " ".join(wordlist[i] for i in indices)
@@ -166,7 +163,12 @@ class ShamirMnemonic(object):
     @classmethod
     def _round_function(cls, i, passphrase, e, salt, r):
         """The round function used internally by the Feistel cipher."""
-        return pbkdf2(pbkdf2.HMAC_SHA256, bytes([i]) + passphrase, salt + r, (cls.MIN_ITERATION_COUNT << e) // cls.ROUND_COUNT).key()[:len(r)]
+        return pbkdf2(
+            pbkdf2.HMAC_SHA256,
+            bytes([i]) + passphrase,
+            salt + r,
+            (cls.MIN_ITERATION_COUNT << e) // cls.ROUND_COUNT,
+        ).key()[: len(r)]
 
     @classmethod
     def _get_salt(cls, identifier):
@@ -227,8 +229,7 @@ class ShamirMnemonic(object):
             )
 
         shares = [
-            (i, random.bytes(len(shared_secret)))
-            for i in range(random_share_count)
+            (i, random.bytes(len(shared_secret))) for i in range(random_share_count)
         ]
 
         random_part = random.bytes(len(shared_secret) - self.DIGEST_LENGTH_BYTES)
@@ -263,8 +264,12 @@ class ShamirMnemonic(object):
         cls, identifier, iteration_exponent, group_index, group_threshold, group_count
     ):
         id_exp_int = (identifier << cls.ITERATION_EXP_LENGTH_BITS) + iteration_exponent
-        return tuple(cls._int_to_indices(id_exp_int, cls.ID_EXP_LENGTH_WORDS, cls.RADIX_BITS)) + (
-            (group_index << 6) + ((group_threshold - 1) << 2) + ((group_count - 1) >> 2),
+        return tuple(
+            cls._int_to_indices(id_exp_int, cls.ID_EXP_LENGTH_WORDS, cls.RADIX_BITS)
+        ) + (
+            (group_index << 6)
+            + ((group_threshold - 1) << 2)
+            + ((group_count - 1) >> 2),
         )
 
     def encode_mnemonic(
@@ -299,9 +304,17 @@ class ShamirMnemonic(object):
 
         share_data = (
             self._group_prefix(
-                identifier, iteration_exponent, group_index, group_threshold, group_count
+                identifier,
+                iteration_exponent,
+                group_index,
+                group_threshold,
+                group_count,
+            )
+            + (
+                (((group_count - 1) & 3) << 8)
+                + (member_index << 4)
+                + (member_threshold - 1),
             )
-            + ((((group_count - 1) & 3) << 8) + (member_index << 4) + (member_threshold - 1),)
             + tuple(self._int_to_indices(value_int, value_word_count, self.RADIX_BITS))
         )
         checksum = self.rs1024_create_checksum(share_data)
@@ -334,8 +347,12 @@ class ShamirMnemonic(object):
         id_exp_int = self._int_from_indices(mnemonic_data[: self.ID_EXP_LENGTH_WORDS])
         identifier = id_exp_int >> self.ITERATION_EXP_LENGTH_BITS
         iteration_exponent = id_exp_int & ((1 << self.ITERATION_EXP_LENGTH_BITS) - 1)
-        tmp = self._int_from_indices(mnemonic_data[self.ID_EXP_LENGTH_WORDS: self.ID_EXP_LENGTH_WORDS + 2])
-        group_index, group_threshold, group_count, member_index,  member_threshold = self._int_to_indices(tmp, 5, 4)
+        tmp = self._int_from_indices(
+            mnemonic_data[self.ID_EXP_LENGTH_WORDS : self.ID_EXP_LENGTH_WORDS + 2]
+        )
+        group_index, group_threshold, group_count, member_index, member_threshold = self._int_to_indices(
+            tmp, 5, 4
+        )
         value_data = mnemonic_data[
             self.ID_EXP_LENGTH_WORDS + 2 : -self.CHECKSUM_LENGTH_WORDS
         ]
@@ -350,7 +367,11 @@ class ShamirMnemonic(object):
         value_byte_count = (10 * len(value_data) - padding_len) // 8
         value_int = self._int_from_indices(value_data)
         if value_data[0] >= 1 << (10 - padding_len):
-            raise MnemonicError('Invalid mnemonic padding for "{} ...".'.format(" ".join(mnemonic.split()[: self.ID_EXP_LENGTH_WORDS + 2])))
+            raise MnemonicError(
+                'Invalid mnemonic padding for "{} ...".'.format(
+                    " ".join(mnemonic.split()[: self.ID_EXP_LENGTH_WORDS + 2])
+                )
+            )
         value = value_int.to_bytes(value_byte_count, "big")
 
         return (
@@ -582,7 +603,11 @@ class ShamirMnemonic(object):
         if len(groups) < group_threshold:
             group_index, group = next(iter(bad_groups.items()))
             prefix = self._group_prefix(
-                identifier, iteration_exponent, group_index, group_threshold, group_count
+                identifier,
+                iteration_exponent,
+                group_index,
+                group_threshold,
+                group_count,
             )
             raise MnemonicError(
                 'Insufficient number of mnemonics. At least {} mnemonics starting with "{} ..." are required.'.format(