input: def count_vowels(string: str) -> int:
      """ Count the number of vowels in the given string.
      >>> count_vowels("Hello, World!")
      3
      >>> count_vowels("Python Programming")
      4
      """
output:     vowels = "aeiouAEIOU"
      count = 0
      for char in string:
          if char in vowels:
              count += 1
      return count