input: 
  def insertionSort(arr):
      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
  
  if __name__ == '__main__':
      arr = [2, 4, 7, 3, 8, 6, 1]
      print(insertionSort(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