input: from typing import List
  
  def avg_list(lst: List[float]) -> float:
      sum = 0
      count = 0
      for i in lst:
          sum += i
          count += 1
      avg = sum / count
      return avg
  
  """
  >>> avg_list([1.0, 2.0, 3.0, 4.0])
  2.5
  >>> avg_list([])
  Traceback (most recent call last):
      ...
  ZeroDivisionError: division by zero
  """
output:     if count == 0:
          raise ZeroDivisionError("division by zero")