input: Write a function to detect if a string contains any vowels. The function should return the first vowel it finds in the string. If no vowels are found, the function should 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("Hll Wrld")==None
  assert vowelCheck("")==None
  assert vowelCheck("Python")=='o'
  assert vowelCheck("AEIOU")=='A'
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