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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def validate_json_file(file_list):
 """ validate JSON testcase format """

    for json_file in set(file_list):
        if not json_file.endswith(".json"):
            logger.log_warning("Only JSON file format can be validated, skip: {}".format(json_file))
            continue

        logger.color_print("Start to validate JSON file: {}".format(json_file), "GREEN")

        with io.open(json_file) as stream:
            try:
                json.load(stream)
            except ValueError as e:
                raise SystemExit(e)

        print("OK")