follow pep8 None should be compared using is or is not

http://legacy.python.org/dev/peps/pep-0008/
## Programming Recommendations
- Comparisons to singletons like None should always be done with is or is not, never the equality operators.

Author: Ken Takagiwa <ken@Kens-MacBook-Pro.local>

Closes #1422 from giwa/apache_master and squashes the following commits:

7b361f3 [Ken Takagiwa] follow pep8 None should be checked using is or is not

1 files changed, 2 insertions, 2 deletions

diff --git a/python/pyspark/cloudpickle.py b/python/pyspark/cloudpickle.py
index eb5dbb8de2..4fda2a9b95 100644
--- a/python/pyspark/cloudpickle.py
+++ b/python/pyspark/cloudpickle.py
@@ -243,10 +243,10 @@ class CloudPickler(pickle.Pickler):
         # if func is lambda, def'ed at prompt, is in main, or is nested, then
         # we'll pickle the actual function object rather than simply saving a
         # reference (as is done in default pickler), via save_function_tuple.
-        if islambda(obj) or obj.func_code.co_filename == '<stdin>' or themodule == None:
+        if islambda(obj) or obj.func_code.co_filename == '<stdin>' or themodule is None:
             #Force server to import modules that have been imported in main
             modList = None
-            if themodule == None and not self.savedForceImports:
+            if themodule is None and not self.savedForceImports:
                 mainmod = sys.modules['__main__']
                 if useForcedImports and hasattr(mainmod,'___pyc_forcedImports__'):
                     modList = list(mainmod.___pyc_forcedImports__)