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