diff --git a/msalign/__init__.py b/msalign/__init__.py
index 5d75336..1508c4f 100644
--- a/msalign/__init__.py
+++ b/msalign/__init__.py
@@ -1,4 +1,5 @@
 """Signal calibration and alignment by reference peaks - copy of MSALIGN function from MATLAB bioinformatics library."""
+
 from typing import List
 
 import numpy as np
diff --git a/msalign/align.py b/msalign/align.py
index f288173..fc0323b 100644
--- a/msalign/align.py
+++ b/msalign/align.py
@@ -1,4 +1,5 @@
 """Main alignment class"""
+
 import logging
 import time
 import typing as ty
diff --git a/msalign/utilities.py b/msalign/utilities.py
index f901883..a19d6d7 100644
--- a/msalign/utilities.py
+++ b/msalign/utilities.py
@@ -1,4 +1,5 @@
 """Various utilities used by the library"""
+
 import time
 import warnings
 from typing import List, Union
diff --git a/tests/test_init.py b/tests/test_init.py
index ca972bb..4c2f259 100644
--- a/tests/test_init.py
+++ b/tests/test_init.py
@@ -1,4 +1,5 @@
 """Tests."""
+
 from msalign import __version__
 
 
diff --git a/tests/test_msalign.py b/tests/test_msalign.py
index bdea18d..62123b0 100644
--- a/tests/test_msalign.py
+++ b/tests/test_msalign.py
@@ -1,4 +1,5 @@
 """Test functions"""
+
 import numpy as np
 import pytest
 from scipy import signal
diff --git a/tests/test_utilities.py b/tests/test_utilities.py
index aa0c2e3..b4f1cc8 100644
--- a/tests/test_utilities.py
+++ b/tests/test_utilities.py
@@ -1,4 +1,5 @@
 """Utilities."""
+
 import numpy as np
 import pytest
 import scipy.interpolate as interpolate