code: def unified(old, new):
          
          for diff in difflib.ndiff(old.splitlines(), new.splitlines()):
              if diff[0] == " ":
                  yield diff
              elif diff[0] == "?":
                  continue
              else:
                  yield termcolor.colored(diff, "red" if diff[0] == "-" else "green", attrs=["bold"])
docs: Returns a generator yielding a unified diff between `old` and `new`.