I wonder how to add namespace into my xml-attribute declaration: "xsi:nil='true'" I have to create a xml like this:

<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <node1 xsi:nil="true" />
</root>
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  1 #!/bin/perl
  2 use strict;
  3 use warnings;
  4 use utf8;
  5 
  6 use XML::Writer;
  7 
  8 
  9 my $ns1 = "http://www.w3.org/2001/XMLSchema-instance";
 10 my $prefixMap = {$ns1 => "xsi"};
 11 
 12 my $writer = new XML::Writer(
 13     OUTPUT => 'self',
 14     DATA_INDENT => 3,
 15     DATA_MODE => 1,
 16     NAMESPACES => 1,
 17     PREFIX_MAP => $prefixMap
 18 );
 19 
 20 $writer->startTag("root");
 21 
 22             $writer->emptyTag("node1", ('nil' => "true"));
 23             $writer->emptyTag("node3", [$ns1, "nil" => "true"]);
 24 $writer->endTag("root");
 25 
 26 print $writer->to_string;
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<root>
   <node1 nil="true" />
   <node3 xsi:nil="xmlns:xsi" http://www.w3.org/2001/XMLSchema-instanc
+e="" />
</root>
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1) I miss the namespace declaratione in the <root> - element

2) If I try to set the namespace on an attribute manualy like:  $writer->emptyTag("node1", ('xsi:nil' => "true")); I get an error: Attribute name 'xsi:nil' contains ':' and the writer terminates.