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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 opt_format(self, fmt):
 """ Set value for format option """

        key = get_enum_key(fmt, FORMATTERS)
        if key is not None:
            self.conf["format"] = key
            print("Set format %r" % key)
        else:
            print("Unknown format %r" % fmt)