input: Write a function to remove vowels from a given string.
  assert removeVowels("A beautiful sun rises in the morning.")=="A btfll sn rs s n th mrnn."
  assert removeVowels("This is a test string.")=="Ths s  tst strng."
  assert removeVowels("Hello World!")=="Hll Wrld!"
output: def removeVowels(s: str) -> str:
      vowels = "aeiouAEIOU"
      return ''.join(char for char in s if char not in vowels)