my $handlers = _registered_handlers($class);
map { push @{ $handlers->{$_} }, $additional_handlers{$_} if $additional_handlers{$_} } keys %$handlers;
}
my $handlers = _registered_handlers($class);
map { push @{ $handlers->{$_} }, $additional_handlers{$_} if $additional_handlers{$_} } keys %$handlers;
}