human
Solve the following python programming problem given the following code:
@ dec.skip_win32 
def test_signal_kernel_subprocesses(self) : 
    self._install_test_kernel () 
    (km, kc) = start_new_kernel (kernel_name = 'signaltest') 
    def execute(cmd) : 
        kc.execute (cmd) 
        reply = kc.get_shell_msg (TIMEOUT) 
        content = reply ['content'] 
        self.assertEqual (content ['status'], 'ok') 
        return content 
self.addCleanup (kc.stop_channels) 
    self.addCleanup (km.shutdown_kernel) 
    N = 5 
    for i in range (N) : 
        execute ('start') 
time.sleep (1) 
    reply = execute ('check') 
    self.assertEqual (km ['user_expressions'] ['poll'], ([None] * N)) 
    kc.execute ('sleep') 
    time.sleep (1) 
    km.interrupt_kernel () 
    reply = kc.get_shell_msg (TIMEOUT) 
    content = reply ['content'] 
    self.assertEqual (content ['status'], 'ok') 
    self.assertEqual (content ['user_expressions'] ['interrupted'], True) 
    for i in range (50) : 
        reply = execute ('check') 
        if (reply ['user_expressions'] ['poll'] != ([(- signal.SIGINT)] * N)) : 
            time.sleep (0.1) 
else : 
            break 
self.assertEqual (reply ['user_expressions'] ['poll'], ([(- signal.SIGINT)] * N)) 

    
    

    Fix the buggy line: self.assertEqual (km ['user_expressions'] ['poll'], ([None] * N))
assistant
#Here is Python program to fix the buggy line: self.

self.assertEqual (reply ['user_expressions'] ['poll'], ([None] * N))