def delete_signing_cert(self, cert_id, user_name=None):
        params = {'CertificateId' : cert_id}
        if user_name:
            params['UserName'] = user_name
        return self.get_response('DeleteSigningCertificate', params)

    #
    # Server Certificates
    #
Delete a signing certificate associated with a user.
dataset/ETHPy150Open darcyliu/storyboard/boto/iam/connection.py/IAMConnection.delete_signing_cert