def METHOD_NAME(self, file_path, op, contents=""):
    if op == "init":
        self.file_wr(file_path, "txt", 'w', contents)
    elif op == "append":
        self.file_wr(file_path, "txt", 'a', "\n[" + self.comm_time.get_time(0) + "]\n")
        self.file_wr(file_path, "txt", 'a', contents)
    else:
        print("op ", op, " not support yet!")