From 65499277016e77abb8bc520544b479549fd55f29 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Skytt=C3=A4?= <ville.skytta@iki.fi>
Date: Sat, 15 Sep 2018 10:07:13 +0300
Subject: [PATCH] Encourage new style string formatting (#87)

---
 docs/development_guidelines.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/docs/development_guidelines.md b/docs/development_guidelines.md
index 51207c4b..c5b06948 100644
--- a/docs/development_guidelines.md
+++ b/docs/development_guidelines.md
@@ -81,3 +81,12 @@ Instead of order the imports manually, use [`isort`](https://github.com/timothyc
 $ pip3 install isort
 $ isort homeassistant/components/sensor/fixer.py 
 ```
+
+### Use new style string formatting
+
+Prefer [new style string formatting](https://www.python.org/dev/peps/pep-3101/) over old.
+
+```python
+"{} {}".format('New', 'style')
+"%s %s" % ('Old', 'style')
+```