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: child.rb
    path of file: ./repos/truffleruby/lib/gems/gems/rexml-3.2.5/lib/rexml
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require_relative "node"

module REXML
  ##
  # A Child object is something contained by a parent, and this class
  # contains methods to support that.  Most user code will not use this
  # class directly.
  class Child
 
    
    def initialize( parent = nil )
      @parent = nil
      # Declare @parent, but don't define it.  The next line sets the
      # parent.
      parent.add( self ) if parent
    end

    # Replaces this object with another object.  Basically, calls
    # Parent.replace_child
    #
    # Returns:: self
    def replace_with( child )
      @parent.replace_child( self, child )
      self
    end

    # Removes this child from the parent.
    #
    # Returns:: self
    def remove
      unless @parent.nil?
        @parent.delete self
      end
      self
    end