def xpath(*args)
      backend.xpath(*args).map { |node| backend.proxy_node.new(node) }
    end
def xpath(*args)
      backend.xpath(*args).map { |node| backend.proxy_node.new(node) }
    end
Initialize abstract ProxyFetcher HTML Document

 @return [Document]

 Searches elements by XPath selector.

 @return [Array<ProxyFetcher::Document::Node>]
   collection of nodes