diff --git a/doc/source/conf.py b/doc/source/conf.py
index 388725e..d658487 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -11,7 +11,6 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-import sys, os
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
diff --git a/pygac/__init__.py b/pygac/__init__.py
index 8c97fc8..d9567fb 100644
--- a/pygac/__init__.py
+++ b/pygac/__init__.py
@@ -30,6 +30,7 @@
         "install').")
 
 import logging
+
 from pygac.configuration import get_config, read_config_file  # noqa
 from pygac.runner import get_reader_class, process_file  # noqa
 
diff --git a/pygac/configuration.py b/pygac/configuration.py
index 9ca301e..9a6e804 100644
--- a/pygac/configuration.py
+++ b/pygac/configuration.py
@@ -27,6 +27,7 @@
 import logging
 import os
 import sys
+
 try:
     import configparser
 except ImportError:
diff --git a/pygac/correct_tsm_issue.py b/pygac/correct_tsm_issue.py
index f940125..7ca3b90 100644
--- a/pygac/correct_tsm_issue.py
+++ b/pygac/correct_tsm_issue.py
@@ -23,10 +23,11 @@
 an orbit contain corrupt data. This module identifies affected pixels and flags
 them with fill values."""
 
-import numpy as np
-import bottleneck as bn
 import datetime
 
+import bottleneck as bn
+import numpy as np
+
 TSM_AFFECTED_INTERVALS_POD = {
     3: [(datetime.datetime(2001, 10, 19, 4, 50), datetime.datetime(2001, 10, 19, 13, 38)),
         (datetime.datetime(2001, 10, 19, 16, 58),
diff --git a/pygac/gac_io.py b/pygac/gac_io.py
index 8b08b2d..79cc262 100644
--- a/pygac/gac_io.py
+++ b/pygac/gac_io.py
@@ -33,7 +33,7 @@
 import h5py
 import numpy as np
 
-from pygac.utils import slice_channel, strip_invalid_lat, check_user_scanlines
+from pygac.utils import check_user_scanlines, slice_channel, strip_invalid_lat
 
 LOG = logging.getLogger(__name__)
 
diff --git a/pygac/gac_pod.py b/pygac/gac_pod.py
index 7700229..9e44575 100644
--- a/pygac/gac_pod.py
+++ b/pygac/gac_pod.py
@@ -30,8 +30,8 @@
 
 import numpy as np
 
-from pygac.pod_reader import PODReader, main_pod
 from pygac.gac_reader import GACReader
+from pygac.pod_reader import PODReader, main_pod
 
 LOG = logging.getLogger(__name__)
 
diff --git a/pygac/gac_reader.py b/pygac/gac_reader.py
index 98f8706..ca82fb8 100644
--- a/pygac/gac_reader.py
+++ b/pygac/gac_reader.py
@@ -28,9 +28,8 @@
 
 import logging
 
-from pygac.reader import Reader, ReaderError
 import pygac.pygac_geotiepoints as gtp
-
+from pygac.reader import Reader, ReaderError
 
 LOG = logging.getLogger(__name__)
 
diff --git a/pygac/klm_reader.py b/pygac/klm_reader.py
index da1f0e0..637a6e7 100644
--- a/pygac/klm_reader.py
+++ b/pygac/klm_reader.py
@@ -36,6 +36,7 @@
 
 import datetime
 import logging
+
 try:
     from enum import IntFlag
 except ImportError:
diff --git a/pygac/lac_pod.py b/pygac/lac_pod.py
index 49f6103..4d730fe 100644
--- a/pygac/lac_pod.py
+++ b/pygac/lac_pod.py
@@ -28,8 +28,8 @@
 
 import numpy as np
 
-from pygac.pod_reader import PODReader, main_pod
 from pygac.lac_reader import LACReader
+from pygac.pod_reader import PODReader, main_pod
 
 LOG = logging.getLogger(__name__)
 
diff --git a/pygac/lac_reader.py b/pygac/lac_reader.py
index e3690f4..a85fb27 100644
--- a/pygac/lac_reader.py
+++ b/pygac/lac_reader.py
@@ -26,9 +26,8 @@
 
 import logging
 
-from pygac.reader import Reader, ReaderError
 import pygac.pygac_geotiepoints as gtp
-
+from pygac.reader import Reader, ReaderError
 
 LOG = logging.getLogger(__name__)
 
diff --git a/pygac/pygac_geotiepoints.py b/pygac/pygac_geotiepoints.py
index 96e5ffb..8fe2510 100644
--- a/pygac/pygac_geotiepoints.py
+++ b/pygac/pygac_geotiepoints.py
@@ -25,7 +25,6 @@
 
 
 import geotiepoints as gtp
-
 import numpy as np
 
 
diff --git a/pygac/runner.py b/pygac/runner.py
index 7fd7214..877dfd1 100644
--- a/pygac/runner.py
+++ b/pygac/runner.py
@@ -31,13 +31,12 @@ class for a given file.
 import logging
 import os
 
+from pygac.configuration import get_config
 from pygac.gac_klm import GACKLMReader
 from pygac.gac_pod import GACPODReader
 from pygac.lac_klm import LACKLMReader
 from pygac.lac_pod import LACPODReader
 from pygac.utils import file_opener
-from pygac.configuration import get_config
-
 
 LOG = logging.getLogger(__name__)
 
diff --git a/pygac/tests/test_angles.py b/pygac/tests/test_angles.py
index 97b5e6b..e3be986 100644
--- a/pygac/tests/test_angles.py
+++ b/pygac/tests/test_angles.py
@@ -28,8 +28,7 @@
 
 import numpy as np
 
-from pygac.utils import (get_absolute_azimuth_angle_diff,
-                         centered_modulus)
+from pygac.utils import centered_modulus, get_absolute_azimuth_angle_diff
 
 
 class TestAngles(unittest.TestCase):
diff --git a/pygac/tests/test_io.py b/pygac/tests/test_io.py
index df3a4cb..edb927a 100644
--- a/pygac/tests/test_io.py
+++ b/pygac/tests/test_io.py
@@ -20,12 +20,14 @@
 """Test the I/O."""
 
 import unittest
+
 try:
     import mock
 except ImportError:
     from unittest import mock
 import numpy as np
 import numpy.testing
+
 import pygac.gac_io as gac_io
 import pygac.utils as utils
 
diff --git a/pygac/tests/test_pod.py b/pygac/tests/test_pod.py
index 40e79b7..e1f1caf 100644
--- a/pygac/tests/test_pod.py
+++ b/pygac/tests/test_pod.py
@@ -21,19 +21,21 @@
 """Test module for the pod reading."""
 
 import datetime as dt
+import sys
 import unittest
+
 import numpy as np
 import numpy.testing
-import sys
+
 try:
     from unittest import mock
 except ImportError:
     import mock
 
 from pygac.clock_offsets_converter import txt as clock_offsets_txt
-from pygac.reader import ReaderError, NoTLEData
 from pygac.gac_pod import GACPODReader
 from pygac.lac_pod import LACPODReader
+from pygac.reader import NoTLEData, ReaderError
 from pygac.tests.utils import CalledWithArray
 
 
diff --git a/pygac/tests/test_slerp.py b/pygac/tests/test_slerp.py
index f225631..f48201f 100644
--- a/pygac/tests/test_slerp.py
+++ b/pygac/tests/test_slerp.py
@@ -25,9 +25,11 @@
 
 
 import unittest
-from pygac.slerp import slerp
+
 import numpy as np
 
+from pygac.slerp import slerp
+
 
 class TestSlerp(unittest.TestCase):
 
diff --git a/pygac/tests/test_tsm.py b/pygac/tests/test_tsm.py
index 5a21d10..45d3fe8 100644
--- a/pygac/tests/test_tsm.py
+++ b/pygac/tests/test_tsm.py
@@ -21,11 +21,12 @@
 """Test TSM module."""
 
 import unittest
-import pygac.correct_tsm_issue as tsm
 
 import numpy as np
 import numpy.testing
 
+import pygac.correct_tsm_issue as tsm
+
 
 class TSMTest(unittest.TestCase):
     """Test TSM module."""
diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 3361ca1..17aca21 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -31,7 +31,7 @@
 
 import numpy as np
 
-from pygac.utils import file_opener, calculate_sun_earth_distance_correction
+from pygac.utils import calculate_sun_earth_distance_correction, file_opener
 
 
 class TestUtils(unittest.TestCase):
diff --git a/pygac/utils.py b/pygac/utils.py
index 76a7fd9..c283b57 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -22,7 +22,6 @@
 import gzip
 import io
 import logging
-
 from contextlib import contextmanager, nullcontext
 
 import numpy as np
@@ -199,9 +198,9 @@ def _slice(ch, start_line, end_line, update=None):
         ch_slc = ch[start_line:end_line + 1, :].copy()
 
     if update:
-        updated = [_update_scanline(l, start_line, end_line)
-                   if l is not None else None
-                   for l in update]
+        updated = [_update_scanline(line, start_line, end_line)
+                   if line is not None else None
+                   for line in update]
         return ch_slc, updated
 
     return ch_slc