examples/zonediff: fix pylint (singleton-comparison)

diff --git a/examples/zonediff.py b/examples/zonediff.py
index 69851a185fad889c0ce5d918c5687135ed749059..b05d7a46c781816644c8df2e3466c44dc8bbd202 100755 (executable)
--- a/examples/zonediff.py
+++ b/examples/zonediff.py
@@ -238,19 +238,19 @@ The differences shown will be logical differences, not textual differences.
     if opts.use_bzr:
         old = _open(["bzr", "cat", "-r" + oldr, filename],
                     "Unable to retrieve revision %s of %s" % (oldr, filename))
-        if newr != None:
+        if newr is not None:
             new = _open(["bzr", "cat", "-r" + newr, filename],
                         "Unable to retrieve revision %s of %s" % (newr, filename))
     elif opts.use_git:
         old = _open(["git", "show", oldn],
                     "Unable to retrieve revision %s of %s" % (oldr, filename))
-        if newr != None:
+        if newr is not None:
             new = _open(["git", "show", newn],
                         "Unable to retrieve revision %s of %s" % (newr, filename))
     elif opts.use_rcs:
         old = _open(["co", "-q", "-p", "-r" + oldr, filename],
                     "Unable to retrieve revision %s of %s" % (oldr, filename))
-        if newr != None:
+        if newr is not None:
             new = _open(["co", "-q", "-p", "-r" + newr, filename],
                         "Unable to retrieve revision %s of %s" % (newr, filename))
     if not opts.use_vc: