human
Solve the following python programming problem given the following code:
def __spawn(self) : 
    (master, slave) = pty.openpty () 
    devnul = open (os.devnull, 'r') 
    cmd = ((self.cmd + ('-nb::{}'.format (self.port),)) + self.vimrc) 
    self.proc = subprocess.Popen (cmd, stdin = slave, stdout = slave, stderr = devnul, close_fds = True) 
    self.output = os.fdopen (devnul, 'rb') 
    self.input = os.fdopen (master, 'wb') 
    def pump() : 
        self.tty = v = VT100 (self.cols, self.rows, callback = self._update) 
        while True : 
            b = self.output.read (1) 
            if (not b) : 
                break 
v.append (b) 
threading.Thread (target = pump).start () 

    
    

    Fix the buggy line: self.output = os.fdopen (devnul, 'rb')
assistant
#Here is Python code to fix the buggy line: self.

self.output = os.fdopen (master, 'rb')