elsif (exists( $hdr{"Supersedes"} )) {
my $key = calc_cancel_key($user, $hdr{"Supersedes"});
add_cancel_item(\%hdr, 'Cancel-Key', $key);
elsif (exists( $hdr{"Supersedes"} )) {
my $key = calc_cancel_key($user, $hdr{"Supersedes"});
add_cancel_item(\%hdr, 'Cancel-Key', $key);