diff --git a/test/functional/interface_bitcoin_cli.py b/test/functional/interface_bitcoin_cli.py
--- a/test/functional/interface_bitcoin_cli.py
+++ b/test/functional/interface_bitcoin_cli.py
@@ -5,6 +5,7 @@
 """Test bitcoin-cli"""
 
 from decimal import Decimal
+
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
diff --git a/test/functional/interface_rest.py b/test/functional/interface_rest.py
--- a/test/functional/interface_rest.py
+++ b/test/functional/interface_rest.py
@@ -5,14 +5,15 @@
 """Test the REST API."""
 
 import binascii
+import http.client
+import json
+import urllib.parse
 from decimal import Decimal
 from enum import Enum
-import http.client
 from io import BytesIO
-import json
 from struct import pack, unpack
-import urllib.parse
 
+from test_framework.messages import BLOCK_HEADER_SIZE
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
@@ -21,8 +22,6 @@
     hex_str_to_bytes,
 )
 
-from test_framework.messages import BLOCK_HEADER_SIZE
-
 
 class ReqType(Enum):
     JSON = 1
diff --git a/test/functional/interface_rpc.py b/test/functional/interface_rpc.py
--- a/test/functional/interface_rpc.py
+++ b/test/functional/interface_rpc.py
@@ -5,6 +5,7 @@
 """Tests some generic aspects of the RPC interface."""
 
 import os
+
 from test_framework.authproxy import JSONRPCException
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_greater_than_or_equal
diff --git a/test/functional/interface_zmq.py b/test/functional/interface_zmq.py
--- a/test/functional/interface_zmq.py
+++ b/test/functional/interface_zmq.py
@@ -5,15 +5,12 @@
 """Test the ZMQ notification interface."""
 import struct
 from io import BytesIO
+from time import sleep
 
 from test_framework.address import ADDRESS_ECREG_UNSPENDABLE
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import CTransaction, hash256
-from test_framework.util import (
-    assert_equal,
-    connect_nodes,
-)
-from time import sleep
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, connect_nodes
 
 
 def hash256_reversed(byte_str):
diff --git a/test/functional/mempool_accept.py b/test/functional/mempool_accept.py
--- a/test/functional/mempool_accept.py
+++ b/test/functional/mempool_accept.py
@@ -4,21 +4,18 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test mempool acceptance of raw transactions."""
 
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.key import ECKey
 from test_framework.messages import (
+    MAX_BLOCK_BASE_SIZE,
+    MAX_MONEY,
     XEC,
     COutPoint,
     CTransaction,
     CTxOut,
     FromHex,
-    MAX_BLOCK_BASE_SIZE,
     ToHex,
-    MAX_MONEY,
 )
 from test_framework.script import (
-    hash160,
-    CScript,
     OP_0,
     OP_2,
     OP_3,
@@ -26,11 +23,11 @@
     OP_EQUAL,
     OP_HASH160,
     OP_RETURN,
+    CScript,
+    hash160,
 )
-from test_framework.util import (
-    assert_equal,
-    assert_raises_rpc_error,
-)
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, assert_raises_rpc_error
 
 
 class MempoolAcceptanceTest(BitcoinTestFramework):
diff --git a/test/functional/mempool_persist.py b/test/functional/mempool_persist.py
--- a/test/functional/mempool_persist.py
+++ b/test/functional/mempool_persist.py
@@ -35,9 +35,9 @@
     node1 can't write to disk.
 
 """
-from decimal import Decimal
 import os
 import time
+from decimal import Decimal
 
 from test_framework.p2p import P2PTxInvStore
 from test_framework.test_framework import BitcoinTestFramework
diff --git a/test/functional/mempool_reorg.py b/test/functional/mempool_reorg.py
--- a/test/functional/mempool_reorg.py
+++ b/test/functional/mempool_reorg.py
@@ -8,8 +8,8 @@
 that spend (directly or indirectly) coinbase transactions.
 """
 
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.blocktools import create_raw_transaction
+from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_rpc_error
 
 
diff --git a/test/functional/mempool_resurrect.py b/test/functional/mempool_resurrect.py
--- a/test/functional/mempool_resurrect.py
+++ b/test/functional/mempool_resurrect.py
@@ -4,8 +4,8 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test resurrection of mined transactions when the blockchain is re-organized."""
 
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.blocktools import create_raw_transaction
+from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
 
diff --git a/test/functional/mempool_spend_coinbase.py b/test/functional/mempool_spend_coinbase.py
--- a/test/functional/mempool_spend_coinbase.py
+++ b/test/functional/mempool_spend_coinbase.py
@@ -12,8 +12,8 @@
 but less mature coinbase spends are NOT.
 """
 
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.blocktools import create_raw_transaction
+from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_raises_rpc_error
 
 
diff --git a/test/functional/mempool_unbroadcast.py b/test/functional/mempool_unbroadcast.py
--- a/test/functional/mempool_unbroadcast.py
+++ b/test/functional/mempool_unbroadcast.py
@@ -10,11 +10,7 @@
 from test_framework.blocktools import create_confirmed_utxos
 from test_framework.p2p import P2PTxInvStore
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import (
-    assert_equal,
-    connect_nodes,
-    disconnect_nodes,
-)
+from test_framework.util import assert_equal, connect_nodes, disconnect_nodes
 
 # 15 minutes in seconds
 MAX_INITIAL_BROADCAST_DELAY = 15 * 60
diff --git a/test/functional/mempool_updatefromblock.py b/test/functional/mempool_updatefromblock.py
--- a/test/functional/mempool_updatefromblock.py
+++ b/test/functional/mempool_updatefromblock.py
@@ -8,8 +8,8 @@
 when transactions have been re-added from a disconnected block to the mempool.
 """
 import time
-
 from decimal import Decimal
+
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
diff --git a/test/functional/mining_basic.py b/test/functional/mining_basic.py
--- a/test/functional/mining_basic.py
+++ b/test/functional/mining_basic.py
@@ -11,18 +11,9 @@
 import copy
 from decimal import Decimal
 
-from test_framework.blocktools import (
-    create_coinbase,
-    TIME_GENESIS_BLOCK,
-)
-from test_framework.messages import (
-    CBlock,
-    CBlockHeader,
-    BLOCK_HEADER_SIZE,
-)
-from test_framework.p2p import (
-    P2PDataStore,
-)
+from test_framework.blocktools import TIME_GENESIS_BLOCK, create_coinbase
+from test_framework.messages import BLOCK_HEADER_SIZE, CBlock, CBlockHeader
+from test_framework.p2p import P2PDataStore
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
diff --git a/test/functional/mining_getblocktemplate_longpoll.py b/test/functional/mining_getblocktemplate_longpoll.py
--- a/test/functional/mining_getblocktemplate_longpoll.py
+++ b/test/functional/mining_getblocktemplate_longpoll.py
@@ -4,8 +4,8 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test longpolling with getblocktemplate."""
 
-from decimal import Decimal
 import threading
+from decimal import Decimal
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import get_rpc_proxy, random_transaction
diff --git a/test/functional/mining_prioritisetransaction.py b/test/functional/mining_prioritisetransaction.py
--- a/test/functional/mining_prioritisetransaction.py
+++ b/test/functional/mining_prioritisetransaction.py
@@ -10,6 +10,7 @@
     create_confirmed_utxos,
     send_big_transactions,
 )
+
 # FIXME: review how this test needs to be adapted w.r.t _LEGACY_MAX_BLOCK_SIZE
 from test_framework.cdefs import LEGACY_MAX_BLOCK_SIZE
 from test_framework.messages import COIN