def root()
      unless !instance_variable_defined?(:@nodes) || @nodes.nil?
        @nodes.each do |n|
          return n if n.is_a?(::Ox::Element)
        end
      end
      nil
    end
def root()
      unless !instance_variable_defined?(:@nodes) || @nodes.nil?
        @nodes.each do |n|
          return n if n.is_a?(::Ox::Element)
        end
      end
      nil
    end
Create a new Document.
 - +prolog+ [Hash] prolog attributes
   - _:version_ [String] version, typically '1.0' or '1.1'
   - _:encoding_ [String] encoding for the document, currently included but ignored
   - _:standalone_ [String] indicates the document is standalone
 Returns the first Element in the document.