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: targeted_patches.rb
    path of file: ./repos/opal/lib/opal/rewriters
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'opal/rewriters/base'

module Opal
  module Rewriters
    # This module attempts to ru
    
      def on_def(node)
        name, args, body = *node

        if body && body.type == :begin && body.children.length >= 2
          # parser/rubyxx.rb - racc generated code often looks like:
          #
          #     def _reduce_219(val, _values, result)
          #       result = @builder.op_assign(val[0], val[1], val[2])
          #       result
          #     end
          #
          # This converter transform this into just
          #
          #     def _reduce_219(val, _values, result)
          #       @builder.op_assign(val[0], val[1], val[2])
          #     end

          calls = body.children
          assignment, ret = calls.last(2)
          if assignment.type == :lvasgn && ret.type == :lvar &&
             assignment.children.first == ret.children.first

            if calls.length == 2
              node.updated(nil, [name, args, assignment.children[1]])
            else
              calls = calls[0..-3] << assignment.children[1]
              node.updated(nil, [name, args, body.updated(nil, calls)])
            end