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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 make_market(self, crypto, fiat, seperator="_"):
 """ Convert a crypto and fiat to a "market" string. All exchanges use their own format for specifying markets. Subclasses can define their own implementation. """

        return ("%s%s%s" % (
            self.fix_symbol(crypto), seperator, self.fix_symbol(fiat))
        ).lower()