diff --git a/docs/contributing/python_guidelines.rst b/docs/contributing/python_guidelines.rst
index 5fe72872c..95509cc9a 100644
--- a/docs/contributing/python_guidelines.rst
+++ b/docs/contributing/python_guidelines.rst
@@ -4,7 +4,7 @@ Python coding guidelines
 PEP8
 ~~~~
 
-We ask that all Python contributions adhere to the `PEP8 <http://www.python.org/dev/peps/pep-0008/>`_ style guide, apart from the restriction on line length (E501). The `pep8 tool <http://pep8.readthedocs.org/en/latest/>`_ makes it easy to check your code, e.g. ``pep8 --ignore=E501 your_file.py``.
+We ask that all Python contributions adhere to the `PEP8 <http://www.python.org/dev/peps/pep-0008/>`_ style guide, apart from the restriction on line length (E501). In addition, import lines should be sorted according to `isort <http://timothycrosley.github.io/isort/>`_ rules. If you have installed Wagtail's testing dependencies (``pip install -e .[testing]``), you can check your code by running ``make lint``.
 
 
 Python 2 and 3 compatibility