diff --git a/doc/examples/plot_line_hough_transform.py b/doc/examples/plot_line_hough_transform.py
index e19c37d7..cd0ae008 100644
--- a/doc/examples/plot_line_hough_transform.py
+++ b/doc/examples/plot_line_hough_transform.py
@@ -1,4 +1,4 @@
-"""
+r"""
 =============================
 Straight line Hough transform
 =============================
diff --git a/skimage/__init__.py b/skimage/__init__.py
index 23e5d3a7..53d31eae 100644
--- a/skimage/__init__.py
+++ b/skimage/__init__.py
@@ -88,9 +88,7 @@ test_verbose = _functools.partial(test, verbose=True)
 test_verbose.__doc__ = test.__doc__
 
 
-from exceptions import Warning as _Warning
-
-class _Log(_Warning):
+class _Log(Warning):
     pass
 
 class _FakeLog(object):
diff --git a/skimage/_shared/utils.py b/skimage/_shared/utils.py
index 18cd25c9..0909b232 100644
--- a/skimage/_shared/utils.py
+++ b/skimage/_shared/utils.py
@@ -1,7 +1,6 @@
 import warnings
 import functools
 import sys
-from exceptions import Warning
 
 from . import six