new_contents: # Insertion sort
  
  
  def insertionSort(sequence):
      """
      Input: unsorted sequence {a1, a2, a3, ... an}
      Output: permutation of the input sequence such that {a1 <= a2 <= a3 ... an}
      """
      # skip the first element
      for index in list(range(1,len(sequence))):
          # determine which item is currently being evaluated
          current = sequence[index]
  
          # insert into sorted sequence
          i = index - 1
  
          print('i is:\t\t', i)
          print('current is:\t', current)
  
          # sort subarray
          while i >= 0 and sequence[i] > current:
              # shift items over until i is 0 and
              sequence[i + 1] = sequence[i]
  
              # decrement i
              i = i - 1
  
          # assign the current value i (because i is now 0)
          sequence[i + 1] = current
  
          print(sequence)
          print('=' * 18)
  
      return sequence
  
  
  a = [5, 4, 5, 2, 1]
  sortedA = [1, 2, 4, 5, 5]
  insertionSort(a)
  print('sorted √' if a == sortedA else 'not sorted :(')
  
subject: Implement insertion sort