old_contents: '''
  This is a pure python implementation of the heap sort algorithm.
  
  For doctests run following command:
  python -m doctest -v heap_sort.py
  or
  python3 -m doctest -v heap_sort.py
  
  For manual testing run:
  python insertion_sort.py
  '''
  
  from __future__ import print_function
  
  def heapify(unsorted, index, heap_size):
      largest = index
      left_index = 2 * index + 1
      right_index = 2 * index + 2
      if left_index < heap_size and unsorted[left_index] > unsorted[largest]:
          largest = left_index
  
      if right_index < heap_size and unsorted[right_index] > unsorted[largest]:
          largest = right_index
  
      if largest != index:
          unsorted[largest], unsorted[index] = unsorted[index], unsorted[largest]
          heapify(unsorted, largest, heap_size)
  
  def heap_sort(unsorted):
      '''
      Pure implementation of the heap sort algorithm in Python
      :param collection: some mutable ordered collection with heterogeneous
      comparable items inside
      :return: the same collection ordered by ascending
  
      Examples:
      >>> heap_sort([0, 5, 3, 2, 2])
      [0, 2, 2, 3, 5]
  
      >>> heap_sort([])
      []
  
      >>> heap_sort([-2, -5, -45])
      [-45, -5, -2]
      '''
      n = len(unsorted)
      for i in range(n//2 - 1, -1, -1):
          heapify(unsorted, i, n)
      for i in range(n - 1, -1, -1):
          unsorted[0], unsorted[i] = unsorted[i], unsorted[0]
          heapify(unsorted, 0, i)
      return unsorted
  
  if __name__ == '__main__':
      import sys
      if sys.version_info.major < 3:
          input_function = raw_input
      else:
          input_function = input
  
      user_input = input_function('Enter numbers separated by a comma:\n')
      unsorted = [int(item) for item in user_input.split(',')]
      print(heap_sort(unsorted))
  
new_contents: '''
  This is a pure python implementation of the heap sort algorithm.
  
  For doctests run following command:
  python -m doctest -v heap_sort.py
  or
  python3 -m doctest -v heap_sort.py
  
  For manual testing run:
  python heap_sort.py
  '''
  
  from __future__ import print_function
  
  def heapify(unsorted, index, heap_size):
      largest = index
      left_index = 2 * index + 1
      right_index = 2 * index + 2
      if left_index < heap_size and unsorted[left_index] > unsorted[largest]:
          largest = left_index
  
      if right_index < heap_size and unsorted[right_index] > unsorted[largest]:
          largest = right_index
  
      if largest != index:
          unsorted[largest], unsorted[index] = unsorted[index], unsorted[largest]
          heapify(unsorted, largest, heap_size)
  
  def heap_sort(unsorted):
      '''
      Pure implementation of the heap sort algorithm in Python
      :param collection: some mutable ordered collection with heterogeneous
      comparable items inside
      :return: the same collection ordered by ascending
  
      Examples:
      >>> heap_sort([0, 5, 3, 2, 2])
      [0, 2, 2, 3, 5]
  
      >>> heap_sort([])
      []
  
      >>> heap_sort([-2, -5, -45])
      [-45, -5, -2]
      '''
      n = len(unsorted)
      for i in range(n//2 - 1, -1, -1):
          heapify(unsorted, i, n)
      for i in range(n - 1, 0, -1):
          unsorted[0], unsorted[i] = unsorted[i], unsorted[0]
          heapify(unsorted, 0, i)
      return unsorted
  
  if __name__ == '__main__':
      import sys
      if sys.version_info.major < 3:
          input_function = raw_input
      else:
          input_function = input
  
      user_input = input_function('Enter numbers separated by a comma:\n')
      unsorted = [int(item) for item in user_input.split(',')]
      print(heap_sort(unsorted))
  
subject: Update heap_sort.py