check-code: indent 4 spaces in py files

contrib/check-code.py

@@ -206,6 +206,7 b' pypats = ['
     (r'\.debug\(\_', "don't mark debug messages for translation"),
     (r'\.strip\(\)\.split\(\)', "no need to strip before splitting"),
     (r'^\s*except\s*:', "warning: naked except clause", r'#.*re-raises'),
+    (r':\n(    )*( ){1,3}[^ ]', "must indent 4 spaces"),
   ],
   # warnings
   [

mercurial/patch.py

@@ -1630,9 +1630,9 b' def diff(repo, node1=None, node2=None, m'
     if opts.git or opts.upgrade:
         copy = copies.pathcopies(ctx1, ctx2)
 
-    difffn = (lambda opts, losedata:
-                  trydiff(repo, revs, ctx1, ctx2, modified, added, removed,
-                          copy, getfilectx, opts, losedata, prefix))
+    def difffn(opts, losedata):
+        return trydiff(repo, revs, ctx1, ctx2, modified, added, removed,
+                       copy, getfilectx, opts, losedata, prefix)
     if opts.upgrade and not opts.git:
         try:
             def losedata(fn):