foreach my $key ( @keys ) {

    my $foo = $self->{'output'}->{$key};

    if ( ! defined $foo->{'fh'} and $foo->{'type'} ne 'named_pipe' ) {
      croak "undefined fh for key $key\n";
    }

    given ( $foo->{'type'} ) {

      when ('named_pipe') {
        open my $handle, '>', $foo->{'name'} or croak "open failed: $!";
        print $handle $input;
        close $handle or croak "close failed: $!";
      }

    }

  }