All of the examples of export creation use top-level directories.  If you try to export a child directory, the module errors out.
 node server {
    class { '::nfs':
      server_enabled => true
    }
    nfs::server::export{ '/data_folder/child_folder':
      ensure  => 'mounted',
    }
  }
Would cause an error if /data_folder doesn't already exist.  I realize that Puppet doesn't create parent directories by design and this module should ensure parent directories are created.