input: 
  def filter_vowels(string: str) -> str:
      """Filter out all the vowels from a given string.
      >>> filter_vowels('hello world')
      'hll wrld'
      >>> filter_vowels('python programming')
      'pythn progrmmng'
      """
      vowels = ('a', 'e', 'i', 'o', 'u')
      return ''.join(c for c in string if c not in vowels)
  
output:     vowels = ('a', 'e', 'i', 'o', 'u')
      return ''.join(c for c in string if c not in vowels)