input: Write a python function to split a string of names into a list and then extract the first and last names.
  assert extract_names("John Doe Jane Smith") == ("John", "Smith")
  assert extract_names("Alice Bob Carol Dan") == ("Alice", "Dan")
  assert extract_names("Eve Frank") == ("Eve", "Frank")
output: def extract_names(names):
      name_list = names.split()
      first_name = name_list[0]
      last_name = name_list[-1]
      return (first_name, last_name)