input: Write a function to reverse the order of words in a given string. The function should take a string as input and return the same string with words in reversed order. If the input string is empty, the function should return an empty string.
  assert reverse_words("Hello World") == "World Hello"
  assert reverse_words("Python is amazing") == "amazing is Python"
  assert reverse_words("SingleWord") == "SingleWord"
  assert reverse_words("") == ""
output: def reverse_words(s):
      words = s.split()
      reversed_words = words[::-1]
      return ' '.join(reversed_words)