input: Write a function to filter out all the vowels from a given string. The function should return a new string containing only the consonants.
  def filter_vowels(string):
      vowels = ('a', 'e', 'i', 'o', 'u')
      return ''.join(c for c in string if c not in vowels)
  
  assert filter_vowels("hello")=="hll"
  assert filter_vowels("world")=="wrld"
  assert filter_vowels("aeiou")==""
  assert filter_vowels("python")=="pythn"
  assert filter_vowels("")==""
output: def filter_vowels(string):
      vowels = ('a', 'e', 'i', 'o', 'u')
      return ''.join(c for c in string if c not in vowels)