You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: node.rb
    path of file: ./repos/truffleruby/lib/gems/gems/rexml-3.2.5/lib/rexml/light
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require_relative '../xmltokens'

module REXML
  module Light
    # Represents a tagged XML element.  Elements are characterized by
    # having children, attributes, and names, and can themselves be
    # children.
    class Node
      NAMESPLIT = /^(?:(#{XMLTokens
    
      def []=( reference, ns, value=nil )
        if reference.kind_of? String
          value = ns unless value
          at( 3 )[reference] = value
        elsif reference.kind_of? Range
          _old_put( Range.new(3+reference.begin, reference.end, reference.exclude_end?), ns )
        else
          if value
            _old_put( 4+reference, ns, value )
          else
            _old_put( 4+reference, ns )
          end