input: Write a python function to check if a string contains vowels using a class method.
  assert StringChecker().containsVowels("hello") == True
  assert StringChecker().containsVowels("sky") == False
  assert StringChecker().containsVowels("APPLE") == True
output: class StringChecker:
      def containsVowels(self, s: str) -> bool:
          vowels = set("aeiouAEIOU")
          return any(char in vowels for char in s)