'disable_empty' => 0, # bool (implied by multiple)
'label_showkey' => 0, # bool
'label_callback' => sub { my $record = shift; return "label"; },
'disable_empty' => 0, # bool (implied by multiple)
'label_showkey' => 0, # bool
'label_callback' => sub { my $record = shift; return "label"; },