From ced3f5656f942eaf6b1f0d08367da83f543ba7c8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fran=C3=A7ois=20Boulogne?= <fboulogne sciunto org>
Date: Sat, 15 Mar 2014 07:42:08 -0400
Subject: [PATCH] DOC: specify range for step

---
 skimage/util/shape.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/skimage/util/shape.py b/skimage/util/shape.py
index f91286c3..95e0a42e 100644
--- a/skimage/util/shape.py
+++ b/skimage/util/shape.py
@@ -111,9 +111,10 @@ def view_as_windows(arr_in, window_shape, step=1):
     window_shape: tuple
         Defines the shape of the elementary n-dimensional orthotope
         (better know as hyperrectangle [1]_) of the rolling window view.
-    step : int
+    step : int, optional
         Number of elements to skip when moving the window forward (by
-        default, move forward by one).
+        default, move forward by one). The value must be equal or larger
+        than one.
 
     Returns
     -------