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class Queue:    ‘‘‘Create a queue object with a given maximum size.    If maxsize is <= 0, the queue size is infinite.    ‘‘‘    def __init__(self, maxsize=0):        self.maxsize = maxsize        self._init(maxsize)        # mutex must be held whenever the queue is mutating.  All methods        # that acquire mutex must release it before returning.  mutex        # is shared between the three conditions, so acquiring and        # releasing the conditions also acquires and releases mutex.        self.mutex = threading.Lock()        # Notify not_empty whenever an item is added to the queue; a        # thread waiting to get is notified then.        self.not_empty = threading.Condition(self.mutex)        # Notify not_full whenever an item is removed from the queue;        # a thread waiting to put is notified then.        self.not_full = threading.Condition(self.mutex)        # Notify all_tasks_done whenever the number of unfinished tasks        # drops to zero; thread waiting to join() is notified to resume        self.all_tasks_done = threading.Condition(self.mutex)        self.unfinished_tasks = 0    def task_done(self):        ‘‘‘Indicate that a formerly enqueued task is complete.        Used by Queue consumer threads.  For each get() used to fetch a task,        a subsequent call to task_done() tells the queue that the processing        on the task is complete.        If a join() is currently blocking, it will resume when all items        have been processed (meaning that a task_done() call was received        for every item that had been put() into the queue).        Raises a ValueError if called more times than there were items        placed in the queue.        ‘‘‘        with self.all_tasks_done:            unfinished = self.unfinished_tasks - 1            if unfinished <= 0:                if unfinished < 0:                    raise ValueError(‘task_done() called too many times‘)                self.all_tasks_done.notify_all()            self.unfinished_tasks = unfinished    def join(self):        ‘‘‘Blocks until all items in the Queue have been gotten and processed.        The count of unfinished tasks goes up whenever an item is added to the        queue. The count goes down whenever a consumer thread calls task_done()        to indicate the item was retrieved and all work on it is complete.        When the count of unfinished tasks drops to zero, join() unblocks.        ‘‘‘        with self.all_tasks_done:            while self.unfinished_tasks:                self.all_tasks_done.wait()    def qsize(self):        ‘‘‘Return the approximate size of the queue (not reliable!).‘‘‘        with self.mutex:            return self._qsize()    def empty(self):        ‘‘‘Return True if the queue is empty, False otherwise (not reliable!).        This method is likely to be removed at some point.  Use qsize() == 0        as a direct substitute, but be aware that either approach risks a race        condition where a queue can grow before the result of empty() or        qsize() can be used.        To create code that needs to wait for all queued tasks to be        completed, the preferred technique is to use the join() method.        ‘‘‘        with self.mutex:            return not self._qsize()    def full(self):        ‘‘‘Return True if the queue is full, False otherwise (not reliable!).        This method is likely to be removed at some point.  Use qsize() >= n        as a direct substitute, but be aware that either approach risks a race        condition where a queue can shrink before the result of full() or        qsize() can be used.        ‘‘‘        with self.mutex:            return 0 < self.maxsize <= self._qsize()    def put(self, item, block=True, timeout=None):        ‘‘‘Put an item into the queue.        If optional args ‘block‘ is true and ‘timeout‘ is None (the default),        block if necessary until a free slot is available. If ‘timeout‘ is        a non-negative number, it blocks at most ‘timeout‘ seconds and raises        the Full exception if no free slot was available within that time.        Otherwise (‘block‘ is false), put an item on the queue if a free slot        is immediately available, else raise the Full exception (‘timeout‘        is ignored in that case).        ‘‘‘        with self.not_full:            if self.maxsize > 0:                if not block:                    if self._qsize() >= self.maxsize:                        raise Full                elif timeout is None:                    while self._qsize() >= self.maxsize:                        self.not_full.wait()                elif timeout < 0:                    raise ValueError("‘timeout‘ must be a non-negative number")                else:                    endtime = time() + timeout                    while self._qsize() >= self.maxsize:                        remaining = endtime - time()                        if remaining <= 0.0:                            raise Full                        self.not_full.wait(remaining)            self._put(item)            self.unfinished_tasks += 1            self.not_empty.notify()    def get(self, block=True, timeout=None):        ‘‘‘Remove and return an item from the queue.        If optional args ‘block‘ is true and ‘timeout‘ is None (the default),        block if necessary until an item is available. If ‘timeout‘ is        a non-negative number, it blocks at most ‘timeout‘ seconds and raises        the Empty exception if no item was available within that time.        Otherwise (‘block‘ is false), return an item if one is immediately        available, else raise the Empty exception (‘timeout‘ is ignored        in that case).        ‘‘‘        with self.not_empty:            if not block:                if not self._qsize():                    raise Empty            elif timeout is None:                while not self._qsize():                    self.not_empty.wait()            elif timeout < 0:                raise ValueError("‘timeout‘ must be a non-negative number")            else:                endtime = time() + timeout                while not self._qsize():                    remaining = endtime - time()                    if remaining <= 0.0:                        raise Empty                    self.not_empty.wait(remaining)            item = self._get()            self.not_full.notify()            return item    def put_nowait(self, item):        ‘‘‘Put an item into the queue without blocking.        Only enqueue the item if a free slot is immediately available.        Otherwise raise the Full exception.        ‘‘‘        return self.put(item, block=False)    def get_nowait(self):        ‘‘‘Remove and return an item from the queue without blocking.        Only get an item if one is immediately available. Otherwise        raise the Empty exception.        ‘‘‘        return self.get(block=False)    # Override these methods to implement other queue organizations    # (e.g. stack or priority queue).    # These will only be called with appropriate locks held    # Initialize the queue representation    def _init(self, maxsize):        self.queue = deque()    def _qsize(self):        return len(self.queue)    # Put a new item in the queue    def _put(self, item):        self.queue.append(item)    # Get an item from the queue    def _get(self):        return self.queue.popleft()

class LifoQueue(Queue):    ‘‘‘Variant of Queue that retrieves most recently added entries first.‘‘‘    def _init(self, maxsize):        self.queue = []    def _qsize(self):        return len(self.queue)    def _put(self, item):        self.queue.append(item)    def _get(self):        return self.queue.pop()

class PriorityQueue(Queue):    ‘‘‘Variant of Queue that retrieves open entries in priority order (lowest first).    Entries are typically tuples of the form:  (priority number, data).    ‘‘‘    def _init(self, maxsize):        self.queue = []    def _qsize(self):        return len(self.queue)    def _put(self, item):        heappush(self.queue, item)    def _get(self):        return heappop(self.queue)

class deque(object):    """    deque([iterable[, maxlen]]) --> deque object        A list-like sequence optimized for data accesses near its endpoints.    """    def append(self, *args, **kwargs): # real signature unknown        """ Add an element to the right side of the deque. """        pass    def appendleft(self, *args, **kwargs): # real signature unknown        """ Add an element to the left side of the deque. """        pass    def clear(self, *args, **kwargs): # real signature unknown        """ Remove all elements from the deque. """        pass    def copy(self, *args, **kwargs): # real signature unknown        """ Return a shallow copy of a deque. """        pass    def count(self, value): # real signature unknown; restored from __doc__        """ D.count(value) -> integer -- return number of occurrences of value """        return 0    def extend(self, *args, **kwargs): # real signature unknown        """ Extend the right side of the deque with elements from the iterable """        pass    def extendleft(self, *args, **kwargs): # real signature unknown        """ Extend the left side of the deque with elements from the iterable """        pass    def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__        """        D.index(value, [start, [stop]]) -> integer -- return first index of value.        Raises ValueError if the value is not present.        """        return 0    def insert(self, index, p_object): # real signature unknown; restored from __doc__        """ D.insert(index, object) -- insert object before index """        pass    def pop(self, *args, **kwargs): # real signature unknown        """ Remove and return the rightmost element. """        pass    def popleft(self, *args, **kwargs): # real signature unknown        """ Remove and return the leftmost element. """        pass    def remove(self, value): # real signature unknown; restored from __doc__        """ D.remove(value) -- remove first occurrence of value. """        pass    def reverse(self): # real signature unknown; restored from __doc__        """ D.reverse() -- reverse *IN PLACE* """        pass    def rotate(self, *args, **kwargs): # real signature unknown        """ Rotate the deque n steps to the right (default n=1).  If n is negative, rotates left. """        pass    def __add__(self, *args, **kwargs): # real signature unknown        """ Return self+value. """        pass    def __bool__(self, *args, **kwargs): # real signature unknown        """ self != 0 """        pass    def __contains__(self, *args, **kwargs): # real signature unknown        """ Return key in self. """        pass    def __copy__(self, *args, **kwargs): # real signature unknown        """ Return a shallow copy of a deque. """        pass    def __delitem__(self, *args, **kwargs): # real signature unknown        """ Delete self[key]. """        pass    def __eq__(self, *args, **kwargs): # real signature unknown        """ Return self==value. """        pass    def __getattribute__(self, *args, **kwargs): # real signature unknown        """ Return getattr(self, name). """        pass    def __getitem__(self, *args, **kwargs): # real signature unknown        """ Return self[key]. """        pass    def __ge__(self, *args, **kwargs): # real signature unknown        """ Return self>=value. """        pass    def __gt__(self, *args, **kwargs): # real signature unknown        """ Return self>value. """        pass    def __iadd__(self, *args, **kwargs): # real signature unknown        """ Implement self+=value. """        pass    def __imul__(self, *args, **kwargs): # real signature unknown        """ Implement self*=value. """        pass    def __init__(self, iterable=(), maxlen=None): # known case of _collections.deque.__init__        """        deque([iterable[, maxlen]]) --> deque object                A list-like sequence optimized for data accesses near its endpoints.        # (copied from class doc)        """        pass    def __iter__(self, *args, **kwargs): # real signature unknown        """ Implement iter(self). """        pass    def __len__(self, *args, **kwargs): # real signature unknown        """ Return len(self). """        pass    def __le__(self, *args, **kwargs): # real signature unknown        """ Return self<=value. """        pass    def __lt__(self, *args, **kwargs): # real signature unknown        """ Return self<value. """        pass    def __mul__(self, *args, **kwargs): # real signature unknown        """ Return self*value.n """        pass    @staticmethod # known case of __new__    def __new__(*args, **kwargs): # real signature unknown        """ Create and return a new object.  See help(type) for accurate signature. """        pass    def __ne__(self, *args, **kwargs): # real signature unknown        """ Return self!=value. """        pass    def __reduce__(self, *args, **kwargs): # real signature unknown        """ Return state information for pickling. """        pass    def __repr__(self, *args, **kwargs): # real signature unknown        """ Return repr(self). """        pass    def __reversed__(self): # real signature unknown; restored from __doc__        """ D.__reversed__() -- return a reverse iterator over the deque """        pass    def __rmul__(self, *args, **kwargs): # real signature unknown        """ Return self*value. """        pass    def __setitem__(self, *args, **kwargs): # real signature unknown        """ Set self[key] to value. """        pass    def __sizeof__(self): # real signature unknown; restored from __doc__        """ D.__sizeof__() -- size of D in memory, in bytes """        pass    maxlen = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default    """maximum size of a deque or None if unbounded"""    __hash__ = None