child("foo") length: 2
child("bar") length: 1
child("XXXXX") length: 0
child("foo") toString: foo1
child("foo") toString: foo2
child("bar") toString: bar1
child("a").length: 1
child("b").length: 0
child("a").@b: c
xml_list.child("b").length(): 3
xml_list.child("c").length(): 1
xml_list.child("unknown").length(): 0
xml_list.child("b"): <b>a1-b1</b>
<b>a1-b2</b>
<b>a2-b</b>
xml_list.child("c"): a2-c
xml_list.child("unknown"): 
