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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 hash_name(self):
 """ The URL-friendly identifier for the item. Generates its own approximation if one isn't available """

        name = self._item.get("market_hash_name")

        if not name:
            name = "{0.appid}-{0.name}".format(self)

        return name