Timed Exit

[Tbot]

What is the final code then?
When I run

class TimeOut:
    def __init__(self, timeout):
        self.timeout = timeout
        self._orig_handler = signal.signal(signal.SIGALRM, self._timeout)
    def __enter__(self):
        signal.alarm(self.timeout)
        return self
    def __exit__(self, *args):
        signal.signal(signal.SIGALRM, self._orig_handler)
    def _timeout(self, *args):
        raise TimeoutError

with TimeOut(5):
    try:
        input('Answer in 5 seconds: ')
    except TimeoutError:
        print('\nTime is up!')

I get:

Error:
Traceback (most recent call last):
  File "Untitled", line 13
    with TimeOut(5):
  File "Untitled", line 4, in __init__
    self._orig_handler = signal.signal(signal.SIGALRM, self._timeout)
NameError: global name 'signal' is not defined