```
% pandoc -t native -s -M title=New
% Old
^D
Pandoc
Meta
{ unMeta = fromList [ ( "title" , MetaString "New" ) ] }
[]
% pandoc -t native -s -M foo=1 -M foo=2
{ unMeta =
fromList
[ ( "foo" , MetaList [ MetaString "1" , MetaString "2" ] ) ]
}