input: Write a python function to convert a string into a list of words.
  assert convert_str_list("This is a test") == ["This", "is", "a", "test"]
  assert convert_str_list("Hello World") == ["Hello", "World"]
  assert convert_str_list("Python is fun") == ["Python", "is", "fun"]
output: def convert_str_list(s):
      return s.split()