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: FindTheMaximumSumOfAContiguousSubarray(kadane'sAlgorithm).rb
    path of file: ./repos/program/program/find-the-maximum-sum-of-a-contiguous-subarray-(kadane's-algorithm)
    
    the code of the file until where you have to start completion: module Subarray

  def self.max_sub(arr)
    
    max_so_far = arr.first
    max_ending_here = 0
    start = 0
    stop = 0
    playhead = 0
    
    arr.each_with_index do |el, i|

      max_e
    
  def self.max_sub(arr)
    
    max_so_far = arr.first
    max_ending_here = 0
    start = 0
    stop = 0
    playhead = 0
    
    arr.each_with_index do |el, i|

      max_ending_here += el
      if max_so_far < max_ending_here
        max_so_far = max_ending_here 
        start = playhead
        stop = i
      end

      if max_ending_here < 0
        max_ending_here = 0 
        playhead = i+1
      end