class Nokogiri::XML::Node

def prepend_child node_or_tags

Also see related method +add_child+.

Returns the reparented node (if +node_or_tags+ is a Node), or NodeSet (if +node_or_tags+ is a DocumentFragment, NodeSet, or string).

+node_or_tags+ can be a Nokogiri::XML::Node, a ::DocumentFragment, a ::NodeSet, or a string containing markup.
Add +node_or_tags+ as the first child of this Node.
## 
def prepend_child node_or_tags
  if first = children.first
    # Mimic the error add_child would raise.
    raise RuntimeError, "Document already has a root node" if is_a?(XML::Document) && !node_or_tags.is_a?(XML::ProcessingInstruction)
    first.__send__(:add_sibling, :previous, node_or_tags)
  else
    add_child(node_or_tags)
  end
end