old_contents: # This program makes a Collatz Sequence for a given number
  
  # Write a function named collatz() that has one parameter named number.
  # If number is even, then collatz() should print number // 2 and return this value.
  # If number is odd, then collatz() should print and return 3 * number + 1.
  
  # Then write a program that lets the user type in an integer and that keeps calling
  # collatz() on that number until the function returns the value 1.
  
  # Sample output:
  # Enter number:
  # 3
  # 10
  # 5
  # 16
  # 8
  # 4
  # 2
  # 1
  
  
  def collatz(number):
      if not number % 2:
          return number // 2
      else:
          return 3 * number + 1
  
  
  def main():
      n = int(input("Input a number: "))
      while n != 1:
          print(n)
          n = collatz(n)
      print(n)  # When n == 1
  
  
  # If program is run (instead of imported), call main():
  if __name__ == "__main__":
      main()
  
new_contents: """Make Collatz Sequence
  
  This program makes a `Collatz Sequence`_ for a given number.
  
  Write a function named :meth:`collatz` that has one parameter named number.
  If number is even, then :meth:`collatz` should print `number // 2` and return this value.
  If number is odd, then :meth:`collatz` should print and return `3 * number + 1`.
  
  Then write a program that lets the user type in an integer and that keeps calling
  :meth:`collatz` on that number until the function returns the value `1`.
  
  Example:
      ::
  
          Enter number:
          3
          10
          5
          16
          8
          4
          2
          1
  
  .. _Collatz Sequence:
      https://en.wikipedia.org/wiki/Collatz_conjecture
  
  """
  
  
  def collatz(number: int) -> int:
      """Collatz
  
      If number is even, then return `number // 2`.
      If number is odd, then return `3 * number + 1`.
  
      Args:
           number: Integer to generate a Collatz conjecture term for.
  
      Returns:
          Integer that is either a quotient or a product and sum.
      """
      if not number % 2:
          return number // 2
      else:
          return 3 * number + 1
  
  
  def main():
      n = int(input("Input a number: "))
      while n != 1:
          print(n)
          n = collatz(n)
      print(n)  # When n == 1
  
  
  # If program is run (instead of imported), call main():
  if __name__ == "__main__":
      main()
  
subject: Update P01_make_collatz_seq.py added docstrings