class Sanitize

def transform_node!(node, node_whitelist, mode)
  @transformers[mode].each do |transformer|
    result = transformer.call({
      :config         => @config,
      :is_whitelisted => node_whitelist.include?(node),
      :node           => node,
      :node_name      => node.name.downcase,
      :node_whitelist => node_whitelist,
      :traversal_mode => mode
    })
    if result.is_a?(Hash) && result[:node_whitelist].respond_to?(:each)
      node_whitelist.merge(result[:node_whitelist])
    end
  end
  node
end