diff --git a/ecdsa/__init__.py b/ecdsa/__init__.py
index e834b3a..539ca99 100644
--- a/ecdsa/__init__.py
+++ b/ecdsa/__init__.py
@@ -1,7 +1,7 @@
 __all__ = ["curves", "der", "ecdsa", "ellipticcurve", "keys", "numbertheory",
            "test_pyecdsa", "util", "six"]
-from .keys import SigningKey, VerifyingKey, BadSignatureError, BadDigestError
 from .curves import NIST192p, NIST224p, NIST256p, NIST384p, NIST521p, SECP256k1
+from .keys import BadDigestError, BadSignatureError, SigningKey, VerifyingKey
 
 _hush_pyflakes = [SigningKey, VerifyingKey, BadSignatureError, BadDigestError,
                   NIST192p, NIST224p, NIST256p, NIST384p, NIST521p, SECP256k1]
diff --git a/ecdsa/_version.py b/ecdsa/_version.py
index 3e833e6..75c9950 100644
--- a/ecdsa/_version.py
+++ b/ecdsa/_version.py
@@ -17,7 +17,12 @@ tag_prefix = "python-ecdsa-"
 parentdir_prefix = "ecdsa-"
 versionfile_source = "ecdsa/_version.py"
 
-import os, sys, re, subprocess, errno
+import errno
+import os
+import re
+import subprocess
+import sys
+
 
 def run_command(commands, args, cwd=None, verbose=False, hide_stderr=False):
     assert isinstance(commands, list)
diff --git a/ecdsa/der.py b/ecdsa/der.py
index b045952..ba58efc 100644
--- a/ecdsa/der.py
+++ b/ecdsa/der.py
@@ -1,8 +1,10 @@
 from __future__ import division
 
-import binascii
 import base64
-from .six import int2byte, b, integer_types, text_type
+import binascii
+
+from .six import b, int2byte, integer_types, text_type
+
 
 class UnexpectedDER(Exception):
     pass
diff --git a/ecdsa/ecdsa.py b/ecdsa/ecdsa.py
index 4eb2d39..b9cf827 100644
--- a/ecdsa/ecdsa.py
+++ b/ecdsa/ecdsa.py
@@ -53,11 +53,11 @@ Revision history:
 Written in 2005 by Peter Pearson and placed in the public domain.
 """
 
-from .six import int2byte, b, print_
-from . import ellipticcurve
-from . import numbertheory
 import random
 
+from . import ellipticcurve
+from . import numbertheory
+from .six import b, int2byte, print_
 
 
 class Signature( object ):
diff --git a/ecdsa/ellipticcurve.py b/ecdsa/ellipticcurve.py
index 390bb35..dc9a42c 100644
--- a/ecdsa/ellipticcurve.py
+++ b/ecdsa/ellipticcurve.py
@@ -34,8 +34,9 @@
 
 from __future__ import division
 
-from .six import print_
 from . import numbertheory
+from .six import print_
+
 
 class CurveFp( object ):
   """Elliptic Curve over the field of integers modulo a prime."""
diff --git a/ecdsa/keys.py b/ecdsa/keys.py
index 5b52125..032bb7f 100644
--- a/ecdsa/keys.py
+++ b/ecdsa/keys.py
@@ -1,14 +1,15 @@
 import binascii
+from hashlib import sha1
 
-from . import ecdsa
 from . import der
+from . import ecdsa
 from . import rfc6979
 from .curves import NIST192p, find_curve
-from .util import string_to_number, number_to_string, randrange
-from .util import sigencode_string, sigdecode_string
-from .util import oid_ecPublicKey, encoded_oid_ecPublicKey
 from .six import PY3, b
-from hashlib import sha1
+from .util import encoded_oid_ecPublicKey, oid_ecPublicKey
+from .util import number_to_string, randrange, string_to_number
+from .util import sigdecode_string, sigencode_string
+
 
 class BadSignatureError(Exception):
     pass
diff --git a/ecdsa/numbertheory.py b/ecdsa/numbertheory.py
index 7ace0dc..b20d60f 100644
--- a/ecdsa/numbertheory.py
+++ b/ecdsa/numbertheory.py
@@ -11,11 +11,11 @@
 
 from __future__ import division
 
-from .six import print_, integer_types
-from .six.moves import reduce
-
 import math
 
+from .six import integer_types, print_
+from .six.moves import reduce
+
 
 class Error( Exception ):
   """Base class for exceptions in this module."""
diff --git a/ecdsa/rfc6979.py b/ecdsa/rfc6979.py
index 6190ebd..a792598 100644
--- a/ecdsa/rfc6979.py
+++ b/ecdsa/rfc6979.py
@@ -11,8 +11,9 @@ Many thanks to Coda Hale for his implementation in Go language:
 
 import hmac
 from binascii import hexlify
-from .util import number_to_string, number_to_string_crop
+
 from .six import b
+from .util import number_to_string, number_to_string_crop
 
 try:
     bin(0)
diff --git a/ecdsa/test_pyecdsa.py b/ecdsa/test_pyecdsa.py
index 326cac4..2a8c5b4 100644
--- a/ecdsa/test_pyecdsa.py
+++ b/ecdsa/test_pyecdsa.py
@@ -1,24 +1,25 @@
-from __future__ import with_statement, division
+from __future__ import division, with_statement
 
-import unittest
 import os
-import time
 import shutil
 import subprocess
+import time
+import unittest
 from binascii import hexlify, unhexlify
 from hashlib import sha1, sha256, sha512
 
-from .six import b, print_, binary_type
-from .keys import SigningKey, VerifyingKey
-from .keys import BadSignatureError
+from . import der
+from . import rfc6979
 from . import util
-from .util import sigencode_der, sigencode_strings
-from .util import sigdecode_der, sigdecode_strings
 from .curves import Curve, UnknownCurveError
 from .curves import NIST192p, NIST224p, NIST256p, NIST384p, NIST521p, SECP256k1
 from .ellipticcurve import Point
-from . import der
-from . import rfc6979
+from .keys import BadSignatureError
+from .keys import SigningKey, VerifyingKey
+from .six import b, binary_type, print_
+from .util import sigdecode_der, sigdecode_strings
+from .util import sigencode_der, sigencode_strings
+
 
 class SubprocessError(Exception):
     pass
diff --git a/ecdsa/util.py b/ecdsa/util.py
index c51ed3d..206d038 100644
--- a/ecdsa/util.py
+++ b/ecdsa/util.py
@@ -1,12 +1,13 @@
 from __future__ import division
 
-import os
-import math
 import binascii
+import math
+import os
 from hashlib import sha256
+
 from . import der
 from .curves import orderlen
-from .six import PY3, int2byte, b, next
+from .six import PY3, b, int2byte, next
 
 # RFC5480:
 #   The "unrestricted" algorithm identifier is:
diff --git a/espefuse.py b/espefuse.py
index e9725ff..7985b94 100755
--- a/espefuse.py
+++ b/espefuse.py
@@ -15,15 +15,16 @@
 # You should have received a copy of the GNU General Public License along with
 # this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
 # Street, Fifth Floor, Boston, MA 02110-1301 USA.
-from __future__ import print_function, division
+from __future__ import division, print_function
 
-import esptool
 import argparse
-import sys
 import os
 import struct
+import sys
 import time
 
+import esptool
+
 # Table of efuse values - (category, block, word in block, mask, write disable bit, read disable bit, register name, type, description)
 # Match values in efuse_reg.h & Efuse technical reference chapter
 EFUSES = [
diff --git a/espsecure.py b/espsecure.py
index 1d09e2d..0859b18 100755
--- a/espsecure.py
+++ b/espsecure.py
@@ -15,16 +15,17 @@
 # You should have received a copy of the GNU General Public License along with
 # this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
 # Street, Fifth Floor, Boston, MA 02110-1301 USA.
-from __future__ import print_function, division
+from __future__ import division, print_function
 
-import esptool
 import argparse
-import sys
-import os
 import hashlib
+import os
 import struct
-import pyaes
+import sys
+
 import ecdsa
+import esptool
+import pyaes
 
 
 def get_chunks(source, chunk_len):
diff --git a/esptool.py b/esptool.py
index 5e783bb..4c2d1ee 100755
--- a/esptool.py
+++ b/esptool.py
@@ -16,21 +16,22 @@
 # this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
 # Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-from __future__ import print_function, division
+from __future__ import division, print_function
 
 import argparse
+import base64
+import copy
 import hashlib
 import inspect
+import io
 import os
-import serial
+import shlex
 import struct
 import sys
 import time
-import base64
 import zlib
-import shlex
-import copy
-import io
+
+import serial
 
 __version__ = "2.2-dev"
 
diff --git a/flasher_stub/compare_stubs.py b/flasher_stub/compare_stubs.py
index f17311d..757493f 100755
--- a/flasher_stub/compare_stubs.py
+++ b/flasher_stub/compare_stubs.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-import sys, os.path, json
+import sys
 
 # Compare the esptool stub loaders to freshly built ones
 # in the build directory
diff --git a/flasher_stub/esptool_test_stub.py b/flasher_stub/esptool_test_stub.py
index 926a209..3f242ec 100755
--- a/flasher_stub/esptool_test_stub.py
+++ b/flasher_stub/esptool_test_stub.py
@@ -11,7 +11,8 @@
 # the terms of the GNU General Public License as published by the Free Software
 # Foundation; either version 2 of the License, or (at your option) any later version.
 #
-import sys, os.path, json
+import os.path
+import sys
 
 THIS_DIR=os.path.dirname(sys.argv[0])
 
diff --git a/flasher_stub/wrap_stub.py b/flasher_stub/wrap_stub.py
index 2f7761d..6cdbf24 100755
--- a/flasher_stub/wrap_stub.py
+++ b/flasher_stub/wrap_stub.py
@@ -18,10 +18,10 @@
 # Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 import base64
-import zlib
 import os
 import os.path
 import sys
+import zlib
 
 sys.path.append('..')
 import esptool
diff --git a/pyaes/__init__.py b/pyaes/__init__.py
index 5712f79..ea65dbd 100644
--- a/pyaes/__init__.py
+++ b/pyaes/__init__.py
@@ -48,6 +48,6 @@
 
 VERSION = [1, 3, 0]
 
-from .aes import AES, AESModeOfOperationCTR, AESModeOfOperationCBC, AESModeOfOperationCFB, AESModeOfOperationECB, AESModeOfOperationOFB, AESModesOfOperation, Counter
-from .blockfeeder import decrypt_stream, Decrypter, encrypt_stream, Encrypter
-from .blockfeeder import PADDING_NONE, PADDING_DEFAULT
+from .aes import AES, AESModeOfOperationCBC, AESModeOfOperationCFB, AESModeOfOperationCTR, AESModeOfOperationECB, AESModeOfOperationOFB, AESModesOfOperation, Counter
+from .blockfeeder import Decrypter, Encrypter, decrypt_stream, encrypt_stream
+from .blockfeeder import PADDING_DEFAULT, PADDING_NONE
diff --git a/setup.py b/setup.py
index 68dbf68..e5d18fd 100644
--- a/setup.py
+++ b/setup.py
@@ -1,10 +1,11 @@
 from __future__ import division, print_function
 
-from setuptools import setup
 import io
 import os
 import re
 
+from setuptools import setup
+
 
 # Example code to pull version from esptool.py with regex, taken from
 # http://python-packaging-user-guide.readthedocs.org/en/latest/single_source_version/
diff --git a/test/test_esptool.py b/test/test_esptool.py
index e139e8b..4304839 100755
--- a/test/test_esptool.py
+++ b/test/test_esptool.py
@@ -8,15 +8,14 @@ Chip name & serial port are passed in as arguments to test. Same test suite
 runs on esp8266 & esp32 (some addresses will change, see below.)
 
 """
-import subprocess
-import unittest
-import sys
-import os.path
 import os
-import tempfile
-import warnings
-import time
+import os.path
 import re
+import subprocess
+import sys
+import tempfile
+import time
+import unittest
 
 # point is this file is not 4 byte aligned in length
 NODEMCU_FILE = "nodemcu-master-7-modules-2017-01-19-11-10-03-integer.bin"
diff --git a/test/test_imagegen.py b/test/test_imagegen.py
index 1bce63c..d69f063 100755
--- a/test/test_imagegen.py
+++ b/test/test_imagegen.py
@@ -1,10 +1,7 @@
 #!/usr/bin/env python
 import os.path
-import glob
-import sys
 import subprocess
-import difflib
-import warnings
+import sys
 import unittest
 
 from elftools.elf.elffile import ELFFile