old_contents: 
  def hotpo(n):
      if n % 2 == 0:
          return n / 2
      else:
          return 3 * n + 1
  
  def collatz(n, acc = 0):
      if n == 1:
          return acc
      else:
          return collatz(hotpo(n), acc + 1)
  
  
new_contents: #!/usr/bin/env python
  import argparse
  
  def hotpo(n):
      if n % 2 == 0:
          return n / 2
      else:
          return 3 * n + 1
  
  def collatz(n, acc = 0):
      if n == 1:
          return acc
      else:
          return collatz(hotpo(n), acc + 1)
  
  if __name__ == '__main__':
      # create cli arguments
      parser = argparse.ArgumentParser()
      parser.add_argument("num", type=int)
      args = parser.parse_args()
  
      num = args.num
      count = collatz(num)
  
      print("\nCollatz Conjecture for %d" % num)
      print("Reached 1 in %d steps.\n" % count)
  
  
subject: add "main" method to match original output