input: plaintext
  def insertionSort(arr):
      """
      Sorts a list of numbers using the Insertion Sort algorithm.
      >>> insertionSort([2, 4, 7, 3, 8, 6, 1])
      [1, 2, 3, 4, 6, 7, 8]
      >>> insertionSort([10, 9, 8, 7, 6, 5, 4, 3, 2, 1])
      [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
      """
      for i in range(1, len(arr)):
          current = arr[i]
          j = i - 1
          while j >= 0 and arr[j] > current:
              arr[j + 1] = arr[j]
              j -= 1
          arr[j + 1] = current
      return arr
  
output:     for i in range(1, len(arr)):
          current = arr[i]
          j = i - 1
          while j >= 0 and arr[j] > current:
              arr[j + 1] = arr[j]
              j -= 1
          arr[j + 1] = current
      return arr