Clean up JSON Schema Compiler.

tools/json_schema_compiler/json_schema.py

Index: tools/json_schema_compiler/json_schema.py
diff --git a/tools/json_schema_compiler/json_schema.py b/tools/json_schema_compiler/json_schema.py
index 0fa1ba57e9669379d75f1909215dc751816fe54d..ae126c2de911251418b608558d6c5b027e81b42b 100644
--- a/tools/json_schema_compiler/json_schema.py
+++ b/tools/json_schema_compiler/json_schema.py
@@ -3,11 +3,8 @@
 # found in the LICENSE file.
 
 import copy
-import os
-import sys
 
 import json_parse
-import schema_util
 
 def DeleteNodes(item, delete_key):
   """Deletes the given nodes in item, recursively, that have |delete_key| as
@@ -31,15 +28,18 @@ def DeleteNodes(item, delete_key):
 
   return item
 
+
 def Load(filename):
   with open(filename, 'r') as handle:
     schemas = json_parse.Parse(handle.read())
   return schemas
 
+
 # A dictionary mapping |filename| to the object resulting from loading the JSON
 # at |filename|.
 _cache = {}
 
+
 def CachedLoad(filename):
   """Equivalent to Load(filename), but caches results for subsequent calls"""
   if filename not in _cache: