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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 available_options(self):
 """Return options that can be used given the current cmd line rtype: command.Option generator """

        for option in list(self.cmd.options.values()):
            if (option.is_multiple or
                    option not in list(self.used_options)):
                yield option