Looks up locations for this country and postal code.

def postalCodeLookup(self, countryCode, postalCode):
        """
        Looks up locations for this country and postal code.
        """
        params = {"country": countryCode, "postalcode": postalCode}
        d = self._call("postalCodeLookupJSON", params)
        d.addCallback(operator.itemgetter("postalcodes"))
        return d