diff --git a/pyplink/pyplink.py b/pyplink/pyplink.py
index 912a52a..41458f3 100644
--- a/pyplink/pyplink.py
+++ b/pyplink/pyplink.py
@@ -32,7 +32,7 @@
 from io import UnsupportedOperation
 
 try:
-    from itertools import zip_longest as zip_longest
+    from itertools import zip_longest
 except ImportError:
     from itertools import izip_longest as zip_longest
 
@@ -243,7 +243,7 @@ def _read_bim(self):
             bim = bim.set_index("snp", verify_integrity=True)
             self._has_duplicated = False
 
-        except ValueError as e:
+        except ValueError:
             # Setting this flag to true
             self._has_duplicated = True
 
diff --git a/pyplink/tests/__init__.py b/pyplink/tests/__init__.py
index 4db9c69..997ebf4 100644
--- a/pyplink/tests/__init__.py
+++ b/pyplink/tests/__init__.py
@@ -1,3 +1,4 @@
+"""Test module."""
 # This file is part of pyplink.
 #
 # The MIT License (MIT)
diff --git a/pyplink/tests/__main__.py b/pyplink/tests/__main__.py
index 96cdc50..0d65821 100644
--- a/pyplink/tests/__main__.py
+++ b/pyplink/tests/__main__.py
@@ -1,3 +1,4 @@
+"""Main script for tests."""
 # This file is part of pyplink.
 #
 # The MIT License (MIT)
diff --git a/pyplink/tests/test_pyplink.py b/pyplink/tests/test_pyplink.py
index f5ccce5..0d4090c 100644
--- a/pyplink/tests/test_pyplink.py
+++ b/pyplink/tests/test_pyplink.py
@@ -1,3 +1,4 @@
+"""PyPlink test suite."""
 # This file is part of pyplink.
 #
 # The MIT License (MIT)