input: Write a function to detect the vowel in a given string. The function should return the first vowel found in the input string. If no vowel is 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("Pythn")==None
  assert vowelCheck("AEIOU")=='A'
  assert vowelCheck("")==None
  assert vowelCheck("12345")==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