func_code: def countdown(num=3):
      if num != 0:
          print(num)
          countdown(num - 1)
      else:
          print('LIFT OFF!')
  
  
  def search(ls, val):
      i = 0
      while i < len(ls):
          if ls[i] == val:
              return True
          i = i + 1
      return False
  
  
  def index(ls, val):
      i = 0
      while i < len(ls):
          if ls[i] == val:
              return i
          i = i + 1
      return -1
  
  
  def fibonacci(n):
      import math
      Phi = 1.61803398875
      return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))