import signal
# Register an handler for the timeout
def handler(signum, frame):
     print("Forever is over!")
     raise Exception("end of time")
# This function *may* run for an indetermined time...
def loop_forever():
    html_codes = requests.get('https://books.google.ru/books?isbn=3659226408').text
# Register the signal function handler
signal.signal(signal.SIGALRM, handler)
# Define a timeout for your function
signal.alarm(3)
try:
     loop_forever()
except Exception:
     print('!')

 import multiprocessing.pool
import functools
def timeout(max_timeout):
    """Timeout decorator, parameter in seconds."""
    def timeout_decorator(item):
        """Wrap the original function."""
        @functools.wraps(item)
        def func_wrapper(*args, **kwargs):
            """Closure for function."""
            pool = multiprocessing.pool.ThreadPool(processes=1)
            async_result = pool.apply_async(item, args, kwargs)
            # raises a TimeoutError if execution exceeds max_timeout
            return async_result.get(max_timeout)
        return func_wrapper
    return timeout_decorator