input: from typing import Dict
  
  def count_vowels(string: str) -> Dict[str, int]:
      """ Count the number of each vowel in a given string and return a dictionary with the counts.
      Vowels are defined as 'a', 'e', 'i', 'o', 'u' (both uppercase and lowercase).
      >>> count_vowels("hello world!")
      {'a': 0, 'e': 1, 'i': 0, 'o': 2, 'u': 0}
      >>> count_vowels("HOw aRe You?")
      {'a': 1, 'e': 1, 'i': 0, 'o': 2, 'u': 1}
      """
output:     vowels = 'aeiouAEIOU'
      vowel_count = {'a': 0, 'e': 0, 'i': 0, 'o': 0, 'u': 0}
      
      for char in string:
          if char in vowels:
              vowel_count[char.lower()] += 1
      
      return vowel_count