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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 exportCertificate(self, certName, outFolder=None):
 """ This operation downloads an SSL certificate. The file returned by the server is an X.509 certificate. The downloaded certificate can be imported into a client that is making HTTP requests. Inputs: certName - name of the cert to export outFolder - folder on disk to save the certificate. """

        params = {"f" : "json"}
        url = self._url + "/sslCertificates/{cert}/export".format(
            cert=certName)
        if outFolder is None:
            outFolder = tempfile.gettempdir()
        return self._post(url=url, param_dict=params,
                          out_folder=outFolder,
                          proxy_port=self._proxy_port,
                          proxy_url=self._proxy_url)