human
Solve the following python programming problem given the following code:
@ contextmanager 
def downloadStream(self) : 
    (readable_fh, writable_fh) = os.pipe () 
    with os.fdopen (readable_fh, 'r') as readable : 
        with os.fdopen (writable_fh, 'w') as writable : 
            def writer() : 
                try : 
                    if (self.content is not None) : 
                        writable.write (self.content) 
else : 
                        if self.version : 
                            headers = self._s3EncryptionHeaders () 
                            key = self.outer.filesBucket.get_key (self.fileID, validate = False) 
                            key.get_contents_to_file (writable, headers = headers, version_id = self.version) 
else : 
                            assert False 
finally : 
                    writable.close () 
thread = ExceptionalThread (target = self) 
            thread.start () 
            (yield readable) 
            thread.join () 

    
    

    Fix the buggy line: thread = ExceptionalThread (target = self)
assistant
#Here is Python program to fix the buggy line: thread = ExceptionalThread (target = self)
.

thread = ExceptionalThread (target = def writer()