input: 
  def insertion_sort(arr):
      for i in range(1, len(arr)): 
          key = arr[i] 
          # Move elements of arr[0..i-1], 
          # that are greater than key, 
          # to one position ahead of 
          # their current position 
          j = i-1
          while j >= 0 and key < arr[j] : 
                  arr[j + 1] = arr[j] 
                  j -= 1
          arr[j + 1] = key
  
  # Test cases
  # Example 1
  # Input: [12, 11, 13, 5, 6]
  # Output: [5, 6, 11, 12, 13]
  # Example 2
  # Input: [31, 41, 59, 26, 41, 58]
  # Output: [26, 31, 41, 41, 58, 59]
  
output:     return arr