SimpleXML::addChild() can't add line break when output to a xml

[Martina]

\[code\]<?xml version="1.0" encoding="utf-8"?><items><item><title>title3</title><desc>This is some desc3</desc></item></items>\[/code\]There is no line break between each node element when using asXML() to output?how to make output the file well-structured by adding link break\[code\]<?xml version="1.0" encoding="utf-8"?><items><item><title>title3</title><desc>This is some desc3</desc></item></items>\[/code\]