input: Write a python function to remove vowels from a given string.
  assert removeVowels("hello") == "hll"
  assert removeVowels("beautiful") == "btfl"
  assert removeVowels("aeiou") == ""
output: def removeVowels(s: str) -> str:
      vowels = "aeiouAEIOU"
      return ''.join([char for char in s if char not in vowels])