diff --git a/poky/bitbake/lib/ply/yacc.py b/poky/bitbake/lib/ply/yacc.py
index d50886e..561784f 100644
--- a/poky/bitbake/lib/ply/yacc.py
+++ b/poky/bitbake/lib/ply/yacc.py
@@ -488,7 +488,7 @@
                     # --! DEBUG
                     return result
 
-            if t == None:
+            if t is None:
 
                 # --! DEBUG
                 debug.error('Error  : %s',
@@ -766,7 +766,7 @@
                     n = symstack[-1]
                     return getattr(n,"value",None)
 
-            if t == None:
+            if t is None:
 
                 # We have some kind of parsing error here.  To handle
                 # this, we are going to push the current token onto
@@ -1021,7 +1021,7 @@
                     n = symstack[-1]
                     return getattr(n,"value",None)
 
-            if t == None:
+            if t is None:
 
                 # We have some kind of parsing error here.  To handle
                 # this, we are going to push the current token onto