broken arrays

class myorg::researchfs_exports {

include ::stdlib

$users = []
$clients = []
$mountoptions = "(rw,sync,no_subtree_check)"
$exportroot = "/export/research-homedirs"


# validate variables
validate_array($users)
validate_array($clients)

file { '/etc/exports':
  owner     => 'root',
  group     => 'root',
  content   => template('myorg/nfs_exports.erb')
  }
}