In order to create "<a>1</a><a><b>1</b><b>2</b></a>", you used
to to call .xml([{ :a => 1 }, { :a => [{:b => 1 }, { :b => 2 }] }]).

Now you will only need to call .xml(a: [1, { b: [1, 2] } ])

…melize and #input_xml

This will break code that relies on Ebayr::Request methods
made private. You should not rely on these methods anyway,
since they are, though not private, class internals.