How to use the rebasehelper.helpers.process_helper.ProcessHelper.run_subprocess function in rebasehelper

def is_available(cls):
        try:
            return ProcessHelper.run_subprocess([cls.CMD, '--help'], output_file=ProcessHelper.DEV_NULL) == 0
        except (IOError, OSError):
            return False

def is_available(cls):
        try:
            return ProcessHelper.run_subprocess([cls.CMD, '--help'], output_file=ProcessHelper.DEV_NULL) == 0
        except (IOError, OSError):
            return False

"""
        logger.info("Building RPMs")
        output = os.path.join(results_dir, "mock_output.log")

        cmd = [cls.CMD, '--old-chroot', '--rebuild', srpm, '--resultdir', results_dir]
        if root is not None:
            cmd.extend(['--root', root])
        if arch is not None:
            cmd.extend(['--arch', arch])
        if builder_options is not None:
            cmd.extend(builder_options)

        if not check_mock_privileges():
            cmd = ['pkexec'] + cmd

        ret = ProcessHelper.run_subprocess(cmd, output_file=output)
        logs = []
        for log in PathHelper.find_all_files(results_dir, '*.log'):
            logs.append(os.path.join(rpm_results_dir, os.path.basename(log)))

        if ret == 0:
            return [f for f in PathHelper.find_all_files(results_dir, '*.rpm') if not f.endswith('.src.rpm')], logs
        else:
            logfile = get_mock_logfile_path(ret, rpm_results_dir, tmp_path=results_dir)
        raise BinaryPackageBuildError("Building RPMs failed!", rpm_results_dir, logfile=logfile, logs=logs)