def extract(self, package_name):
        """Extract given package."""
        for cmd in ['rpm2cpio', 'cpio']:
            if not Cmd.which(cmd):
                message = '{0} command not found. Install {0}.'.format(cmd)
                raise InstallError(message)

        pattern = '{0}*{1}.rpm'.format(package_name, self.arch)
        rpm_files = Cmd.find('.', pattern)
        if not rpm_files:
            raise InstallError('PRM file not found.')
        cmd = 'rpm2cpio {0} | cpio -idmv'.format(rpm_files[0])
        Cmd.sh_e(cmd)
Extract given package.