diff --git a/pictureshow/__init__.py b/pictureshow/__init__.py
index 8b264d4..d1ac5cd 100644
--- a/pictureshow/__init__.py
+++ b/pictureshow/__init__.py
@@ -1,7 +1,7 @@
 from pictureshow.exceptions import PageSizeError, MarginError, LayoutError
 from pictureshow.core import PictureShow, pictures_to_pdf
 
-__version__ = '0.5.0'
+__version__ = '0.6.0'
 
 __all__ = ['__version__', 'PictureShow', 'pictures_to_pdf',
            'PageSizeError', 'MarginError', 'LayoutError']
diff --git a/pictureshow/cli.py b/pictureshow/cli.py
index 07feb85..889cfce 100644
--- a/pictureshow/cli.py
+++ b/pictureshow/cli.py
@@ -50,6 +50,7 @@ def report_results(num_ok, errors, target_path, verbose=False):
 
 
 def _number(number, noun):
+    """Return a repr of amount in correct grammatical number."""
     suffix = 's' if number > 1 else ''
     return f'{number} {noun}{suffix}'
 
diff --git a/tests/unit_test.py b/tests/unit_test.py
index 7b9686a..e55f906 100644
--- a/tests/unit_test.py
+++ b/tests/unit_test.py
@@ -21,6 +21,7 @@
 
 
 def picture():
+    """Return a mock to replace ImageReader objects in tests."""
     image_reader = create_autospec(ImageReader, instance=True)
     image_reader.getSize.return_value = (640, 400)
     return image_reader