Support for the Ruby 2.4 series has ended. See here for reference.
provides a unified clone operation, for REXML::XPathParser to use across multiple Object+ types
 
               # File rexml/xpath_parser.rb, line 33
def dclone
  klone = self.clone
  klone.clear
  self.each{|v| klone << v.dclone}
  klone
end