input: def avg_list(lst):
      sum = 0
      count = 0
      for i in lst:
          sum += i
          count += 1
      avg = sum / count
      return avg
      
  """
  Calculate the average of a list of numbers.
  
  >>> avg_list([1, 2, 3, 4, 5])
  3.0
  >>> avg_list([10, 20, 30, 40, 50])
  30.0
  >>> avg_list([0, 0, 0, 0, 0])
  0.0
  """
output:     if count == 0:
          return 0.0