{
  "$schema" : "http://json-schema.org/draft-03/schema#",
  "type" : "object",
  "extends": [
    {"$ref": "good_schema_1.json"},
    {"$ref": "good_schema_2.json"}
  ],
  "properties" : {
    "c" : {
      "required" : false
    }
  }
}
