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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 _chk_docunknown(args, exp):
 """Return any unknown args."""

        unknown = []
        for arg in args:
            if arg[:2] == '--':
                val = arg[2:]
                if val not in exp:
                    unknown.append(arg)
            elif arg[:1] == '-':
                val = arg[1:]
                if val not in exp:
                    unknown.append(arg)
        if '-h' in unknown or '--help' in unknown:
            return []
        return unknown