The following function returns the first character of a string or the first element of a list: def first(s): return s[0] Add a docstring to this function and type all three lines - def first(s): > return s [0] - at Python's prompt. Now try: \ first('Hello, world') The docstring is displayed for you as a "tip" as soon as you type the opening parenthesis. Now try first. doc (Python uses two underscores on each side to mark special "system" names.) 9. Find a syntax error in the following code: def mystery (n) : "" "Return n cubed.""" return n3