class Aws::Xml::Builder

you may *not* pass a value to the `args` list.
Pass a block if you want to nest XML nodes inside. When doing this,

* [attributes_hash] - self closing element with attributes
* [value, attributes_hash] - inline element with attributes
* [value] - inline element, no attributes
* [] - empty, no value or attributes

The `args` list may contain:

def node(name, ref, *args, &block)
  attrs = args.last.is_a?(Hash) ? args.pop : {}
  attrs = shape_attrs(ref).merge(attrs)
  args << attrs
  @builder.node(name, *args, &block)
end