Add note about Windows icon format
@@ -41,6 +41,10 @@ class Notification(object):
:type app_icon: str
:type timeout: int
:type ticker: str
+
+ .. note::
+ When called on Windows, ``app_icon`` has to be a path to
+ a file in .ICO format.
'''
self._notify(title=title, message=message, app_icon=app_icon,
