input: Write a python function to check if a given string contains all the vowels.
  assert check_vowels('This is a test') == False
  assert check_vowels('Educational input') == True
  assert check_vowels('Quick brown fox jumps over the lazy dog') == True
output: def check_vowels(s):
      vowels = set('aeiou')
      return vowels.issubset(set(s.lower()))