input: from typing import List
  
  def count_vowels(string: str) -> int:
      """
      Accepts a string as an input and returns the total number of vowels in the string.
      
      >>> count_vowels("hello")
      2
      >>> count_vowels("world")
      1
      >>> count_vowels("AeiOu")
      5
      """
output:     vowels = "aeiouAEIOU"
      count = 0
      for char in string:
          if char in vowels:
              count += 1
      return count