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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 reset_option(key):
 """ Reset one or more options to their default value. Pass "all" as argument to reset all options. Available options: parse.full_codestream print.xml print.codestream print.short Parameter --------- key : str Name of a single option. """

    global _options
    if key == 'all':
        _options = copy.deepcopy(_original_options)
    else:
        if key not in _options.keys():
            raise KeyError('{key} not valid.'.format(key=key))
        _options[key] = _original_options[key]