input: from typing import List
  
  def remove_vowels(string: List[str]) -> str:
      """ Remove all vowels from a given string.
      >>> remove_vowels("hello")
      "hll"
      >>> remove_vowels("AEIOUaeiou")
      ""
      """
output:     vowels = "AEIOUaeiou"
      result = [char for char in string if char not in vowels]
      return ''.join(result)