[Puppet Users] Another "function does not return a value" problem

Here's the function:

module Puppet::Parser::Functions
newfunction(:fact_to_array, :type => :rvalue) do |args|
args[0].split(',')
end
end

Here's the class I'm trying to use it in:

class oms::all_config {
file { '/var/lib/oms/config':
source => 'puppet:///deployment/deployment',
recurse => true,
purge => true,
force => true,
ignore => fact_to_array('DIR_1,DIR_2,DIR_3'),
require => Class['oms::oms_directory'],
}
}

Getting the following error when trying to run puppet agent --test on a
remote agent:

Error: Could not retrieve catalog from remote server: Error 400 on SERVER:
Function 'fact_to_array' does not return a value at
/etc/puppet/modules/oms/manifests/init.pp:13 on node oms-2787

I'm out of ideas as to why is it not working. Will appreciate any help on
this.
Thanks ahead