Mine

package{openssh:
  name => $operatingsystem ? {
    debian => 'openssh-server',
    ubuntu => 'openssh-server',
    redhat => 'openssh-server',
    centos => 'openssh-server',
    default => 'openssh',
  },
  category => $operatingsystem ? {
    gentoo => 'net-misc',
    default => '',
  },
   ensure => present,
}