python multithreading and file locking issues -

i have implemented multithreaded code in 2 ways, in both ways got error. explain causes problem?

in version 1, got exception saying 2 arguments passed writekey function instead of one. in version 2, 1 of threads reads empty line, therefore exception raised while processing empty string.

i using locks, shouldn't prevent multiple threads accessing function or file @ same time?

version 1:

class somethread(threading.thread):     def __init__(self, somequeue, lockfile):         threading.thread.__init__(self)         self.myqueue = somequeue         self.myfilelock = lockfile      def writekey(key):         if os.path.exists(os.path.join('.', outfile)):             open(outfile, 'r') fc:                 readkey = int(fc.readline().rstrip())             os.remove(os.path.join('.', outfile))          open(outfile, 'w') fw:             if readkey > key:                 fw.write(str(readkey))             else:                 fw.write(str(key))      def run(self):         while(true):             dict = self.myqueue.get()              self.myfilelock.acquire()             try:                 self.writekey(dict.get("key"))             finally:                 self.myfilelock.release()              self.myqueue.task_done()  populatequeue() # populate queue objects     filelock = threading.lock()  in range(threadnum):     thread = somethread(somequeue, filelock)     thread.setdaemon(true)     thread.start()  somequeue.join() 

version 2:

def writekey(key):     if os.path.exists(os.path.join('.', outfile)):         open(outfile, 'r') fc:             # something...          os.remove(os.path.join('.', outfile))      open(outfile, 'w') fw:         # something...  class somethread(threading.thread):     def __init__(self, somequeue, lockfile):         threading.thread.__init__(self)         self.myqueue = somequeue         self.myfilelock = lockfile      def run(self):         while(true):             dict = self.myqueue.get()              self.myfilelock.acquire()             try:                 writekey(dict.get("key"))             finally:                 myfilelock.release()              self.myqueue.task_done()  # same above .... 

in version 1, def writekey(key) should declared "self" first parameter, i.e.

def writekey(self, key): 

the problem in version 2 less clear. assume empty line being read while reading outfile. normal , indicates end-of-file has been reached. break out of read loop. preferable read file line-by-line in for loop, e.g.

with open(outfile, 'r') fc:     line in fc:         # process line 

the loop terminate naturally upon reaching end-of-file.