Tweak serialize_ast sample to use `with` statements
diff --git a/examples/serialize_ast.py b/examples/serialize_ast.py
index 8add03b..7a71f9b 100644
--- a/examples/serialize_ast.py
+++ b/examples/serialize_ast.py
@@ -26,13 +26,11 @@
# space saving, it needs Pickle's protocol version >= 2.
# The default version is 3 for python 3.x and 1 for python 2.7.
# You can always select the highest available protocol with the -1 argument.
-#
-f = open('ast', 'wb')
-pickle.dump(ast, f, protocol=-1)
-f.close()
-f = open('ast', 'rb')
-ast = pickle.load(f)
-f.close()
+with open('ast', 'wb') as f:
+ pickle.dump(ast, f, protocol=-1)
-ast.show()
+# Deserialize.
+with open('ast', 'rb') as f:
+ ast = pickle.load(f)
+ ast.show()
