input: Write a function to detect if a given string contains any vowels. If it does, return the first vowel found; otherwise, return None.
  def vowelCheck(inputString):
      vowels = ['a','e','i','o','u','A','E','I','O','U']
      for x in inputString:
          if x in vowels:
              return x
  
  assert vowelCheck("Hello World")=='e'
  assert vowelCheck("Pythn")==None
  assert vowelCheck("AI")=='I'
  assert vowelCheck("")==None
  assert vowelCheck("bcd")==None
output: def vowelCheck(inputString):
      vowels = ['a','e','i','o','u','A','E','I','O','U']
      for x in inputString:
          if x in vowels:
              return x