This promise type assures that a balanced XML tree, containing the matching subtree, will be present in the specified node within the XML file. If the subtree is not found, the default promise is to insert the tree into the specified node. The specified node is determined by body-attributes. The promise object referred to is a literal string representation of a balanced XML tree.

code
bundle edit_xml example
{
insert_tree:

  "<Host name=\"cfe_host\"><Alias>cfe_alias</Alias></Host>"
    select_xpath => "/Server/Service/Engine";
}

Note that typically, only a single tree, within a single specified node, is inserted in each insert_tree promise. You may of course have multiple promises that each insert a tree.