class Nokogiri::XML::DocumentFragment

def css(*args)

For more information see Nokogiri::XML::Searchable#css

selectors. For example:
Search this fragment for CSS +rules+. +rules+ must be one or more CSS

call-seq: css *rules, [namespace-bindings, custom-pseudo-class]
## 
def css(*args)
  if children.any?
    children.css(*args) # 'children' is a smell here
  else
    NodeSet.new(document)
  end
end