From a0fc75c7cb335264f46ee1a88f83624734dc4bfe Mon Sep 17 00:00:00 2001
From: John Wiggins <jwiggins@enthought.com>
Date: Fri, 28 Aug 2015 21:10:39 +0200
Subject: [PATCH] Don't use two lines to raise an exception with a short
 message.

---
 skimage/filters/_gaussian.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/skimage/filters/_gaussian.py b/skimage/filters/_gaussian.py
index 643dca05..85b572ca 100644
--- a/skimage/filters/_gaussian.py
+++ b/skimage/filters/_gaussian.py
@@ -94,8 +94,7 @@ def gaussian_filter(image, sigma, output=None, mode='nearest', cval=0,
         warnings.warn(RuntimeWarning(msg))
         multichannel = True
     if np.any(np.asarray(sigma) < 0.0):
-        msg = "Sigma values less than zero are not valid"
-        raise ValueError(msg)
+        raise ValueError("Sigma values less than zero are not valid")
     if multichannel:
         # do not filter across channels
         if not isinstance(sigma, coll.Iterable):