def _make_cached_stream_func(src_func, wrapper_func):
    cache = WeakKeyDictionary()
    def func():
        stream = src_func()
        try:
            rv = cache.get(stream)
        except Exception:
            rv = None
        if rv is not None:
            return rv
        rv = wrapper_func()
        try:
            stream = src_func()  # In case wrapper_func() modified the stream
            cache[stream] = rv
        except Exception:
            pass
        return rv
    return func 

def _make_cached_stream_func(src_func, wrapper_func):
    cache = WeakKeyDictionary()
    def func():
        stream = src_func()
        try:
            rv = cache.get(stream)
        except Exception:
            rv = None
        if rv is not None:
            return rv
        rv = wrapper_func()
        try:
            cache[stream] = rv
        except Exception:
            pass
        return rv
    return func 

def __init__(self, name, value=None, expected_type=None, expected_types=None, allow_none=False):
        self.name = name
        self._values = WeakKeyDictionary()

        if expected_types is not None:
            self.expected_types = expected_types
        else:
            self.expected_types = []

        if expected_type is not None:
            self.expected_types.append(expected_type)
        self.allow_none = allow_none
        self.__doc__ = "Values must be of type {0}".format(self.expected_types)

        if value is not None:
            self.validate(value)
            self.default_value = value 

def __init__(self, clickRadius=2, moveDistance=5, parent=None):
        QtGui.QGraphicsScene.__init__(self, parent)
        self.setClickRadius(clickRadius)
        self.setMoveDistance(moveDistance)
        self.exportDirectory = None
        
        self.clickEvents = []
        self.dragButtons = []
        self.mouseGrabber = None
        self.dragItem = None
        self.lastDrag = None
        self.hoverItems = weakref.WeakKeyDictionary()
        self.lastHoverEvent = None
        self.minDragTime = 0.5  # drags shorter than 0.5 sec are interpreted as clicks
        
        self.contextMenu = [QtGui.QAction("Export...", self)]
        self.contextMenu[0].triggered.connect(self.showExportDialog)
        
        self.exportDialog = None 

def _make_cached_stream_func(src_func, wrapper_func):
    cache = WeakKeyDictionary()
    def func():
        stream = src_func()
        try:
            rv = cache.get(stream)
        except Exception:
            rv = None
        if rv is not None:
            return rv
        rv = wrapper_func()
        try:
            cache[stream] = rv
        except Exception:
            pass
        return rv
    return func 

def __init__(self, providing_args=None, use_caching=False):
        """
        Create a new signal.

        providing_args
            A list of the arguments this signal can pass along in a send() call.
        """
        self.receivers = []
        if providing_args is None:
            providing_args = []
        self.providing_args = set(providing_args)
        self.lock = threading.Lock()
        self.use_caching = use_caching
        # For convenience we create empty caches even if they are not used.
        # A note about caching: if use_caching is defined, then for each
        # distinct sender we cache the receivers that sender has in
        # 'sender_receivers_cache'. The cache is cleaned when .connect() or
        # .disconnect() is called and populated on send().
        self.sender_receivers_cache = weakref.WeakKeyDictionary() if use_caching else {}
        self._dead_receivers = False 

def test_trashcan_16602(self):
        # Issue #16602: when a weakref's target was part of a long
        # deallocation chain, the trashcan mechanism could delay clearing
        # of the weakref and make the target object visible from outside
        # code even though its refcount had dropped to 0.  A crash ensued.
        class C(object):
            def __init__(self, parent):
                if not parent:
                    return
                wself = weakref.ref(self)
                def cb(wparent):
                    o = wself()
                self.wparent = weakref.ref(parent, cb)

        d = weakref.WeakKeyDictionary()
        root = c = C(None)
        for n in range(100):
            d[c] = c = C(c)
        del root
        gc.collect() 

def test_deepcopy_weakkeydict(self):
        class C(object):
            def __init__(self, i):
                self.i = i
        a, b, c, d = [C(i) for i in xrange(4)]
        u = weakref.WeakKeyDictionary()
        u[a] = b
        u[c] = d
        # Keys aren't copied, values are
        v = copy.deepcopy(u)
        self.assertNotEqual(v, u)
        self.assertEqual(len(v), 2)
        self.assertFalse(v[a] is b)
        self.assertFalse(v[c] is d)
        self.assertEqual(v[a].i, b.i)
        self.assertEqual(v[c].i, d.i)
        del c
        self.assertEqual(len(v), 1) 

def __init__(self, providing_args=None, use_caching=False):
        """
        Create a new signal.

        providing_args
            A list of the arguments this signal can pass along in a send() call.
        """
        self.receivers = []
        if providing_args is None:
            providing_args = []
        self.providing_args = set(providing_args)
        self.lock = threading.Lock()
        self.use_caching = use_caching
        # For convenience we create empty caches even if they are not used.
        # A note about caching: if use_caching is defined, then for each
        # distinct sender we cache the receivers that sender has in
        # 'sender_receivers_cache'. The cache is cleaned when .connect() or
        # .disconnect() is called and populated on send().
        self.sender_receivers_cache = weakref.WeakKeyDictionary() if use_caching else {}
        self._dead_receivers = False 

def __init__(self, queue, enqueue_ops):
        """Create a PyQueueRunner.

        When you later call the `create_threads()` method, the `QueueRunner` will
        create one thread for each op in `enqueue_ops`.  Each thread will run its
        enqueue op in parallel with the other threads.  The enqueue ops do not have
        to all be the same op, but it is expected that they all enqueue tensors in
        `queue`.

        Args:
          qnqueue_handler: a python function that transforms
          queue: A `Queue`.
          enqueue_ops: List of enqueue ops to run in threads later.
        """
        self._queue = queue
        self._enqueue_ops = enqueue_ops

        self._lock = threading.Lock()
        # A map from a session object to the number of outstanding queue runner
        # threads for that session.
        self._runs_per_session = weakref.WeakKeyDictionary() 

def connect(self, slot, sender=None):
    if sender:
      if inspect.ismethod(slot):
        if sender not in self._methods_subs:
          self._methods_subs[sender] = weakref.WeakKeyDictionary()

        if slot.__self__ not in self._methods_subs[sender]:
          self._methods_subs[sender][slot.__self__] = set()

        self._methods_subs[sender][slot.__self__].add(slot.__func__)
      else:
        if sender not in self._functions_subs:
          self._functions_subs[sender] = weakref.WeakSet()
        self._functions_subs[sender].add(slot)
    else:
      if inspect.ismethod(slot):
        if slot.__self__ not in self._methods:
          self._methods[slot.__self__] = set()
        self._methods[slot.__self__].add(slot.__func__)
      else:
        self._functions.add(slot) 

def __init__(self, providing_args=None, use_caching=False):
        """
        Create a new signal.

        providing_args
            A list of the arguments this signal can pass along in a send() call.
        """
        self.receivers = []
        if providing_args is None:
            providing_args = []
        self.providing_args = set(providing_args)
        self.lock = threading.Lock()
        self.use_caching = use_caching
        # For convenience we create empty caches even if they are not used.
        # A note about caching: if use_caching is defined, then for each
        # distinct sender we cache the receivers that sender has in
        # 'sender_receivers_cache'. The cache is cleaned when .connect() or
        # .disconnect() is called and populated on send().
        self.sender_receivers_cache = weakref.WeakKeyDictionary() if use_caching else {}
        self._dead_receivers = False 

def test_trashcan_16602(self):
        # Issue #16602: when a weakref's target was part of a long
        # deallocation chain, the trashcan mechanism could delay clearing
        # of the weakref and make the target object visible from outside
        # code even though its refcount had dropped to 0.  A crash ensued.
        class C(object):
            def __init__(self, parent):
                if not parent:
                    return
                wself = weakref.ref(self)
                def cb(wparent):
                    o = wself()
                self.wparent = weakref.ref(parent, cb)

        d = weakref.WeakKeyDictionary()
        root = c = C(None)
        for n in range(100):
            d[c] = c = C(c)
        del root
        gc.collect() 

def test_deepcopy_weakkeydict(self):
        class C(object):
            def __init__(self, i):
                self.i = i
        a, b, c, d = [C(i) for i in xrange(4)]
        u = weakref.WeakKeyDictionary()
        u[a] = b
        u[c] = d
        # Keys aren't copied, values are
        v = copy.deepcopy(u)
        self.assertNotEqual(v, u)
        self.assertEqual(len(v), 2)
        self.assertFalse(v[a] is b)
        self.assertFalse(v[c] is d)
        self.assertEqual(v[a].i, b.i)
        self.assertEqual(v[c].i, d.i)
        del c
        self.assertEqual(len(v), 1) 

def _make_cached_stream_func(src_func, wrapper_func):
    cache = WeakKeyDictionary()
    def func():
        stream = src_func()
        try:
            rv = cache.get(stream)
        except Exception:
            rv = None
        if rv is not None:
            return rv
        rv = wrapper_func()
        try:
            cache[stream] = rv
        except Exception:
            pass
        return rv
    return func 

def connect(self, s, func):
        """
        register *func* to be called when a signal *s* is generated
        func will be called
        """
        self._func_cid_map.setdefault(s, WeakKeyDictionary())
        if func in self._func_cid_map[s]:
            return self._func_cid_map[s][func]

        self._cid += 1
        cid = self._cid
        self._func_cid_map[s][func] = cid
        self.callbacks.setdefault(s, dict())
        proxy = _BoundMethodProxy(func)
        self.callbacks[s][cid] = proxy
        return cid 

def test_trashcan_16602(self):
        # Issue #16602: when a weakref's target was part of a long
        # deallocation chain, the trashcan mechanism could delay clearing
        # of the weakref and make the target object visible from outside
        # code even though its refcount had dropped to 0.  A crash ensued.
        class C(object):
            def __init__(self, parent):
                if not parent:
                    return
                wself = weakref.ref(self)
                def cb(wparent):
                    o = wself()
                self.wparent = weakref.ref(parent, cb)

        d = weakref.WeakKeyDictionary()
        root = c = C(None)
        for n in range(100):
            d[c] = c = C(c)
        del root
        gc.collect() 

def tearDown(self):
        signal.signal(signal.SIGINT, self._default_handler)
        unittest.signals._results = weakref.WeakKeyDictionary()
        unittest.signals._interrupt_handler = None 

def __init__(self, group=None, target=None, name=None, args=(), kwargs={}):
        threading.Thread.__init__(self, group, target, name, args, kwargs)
        self._pid = None
        self._children = weakref.WeakKeyDictionary()
        self._start_called = False
        self._parent = current_process() 

def __init__(self, name, dtype=None, values=None):
        self.name = name
        self.dtype = dtype or 'string'
        self.values = values
        self.value = weakref.WeakKeyDictionary() 

def _async_clients(cls):
        attr_name = '_async_client_dict_' + cls.__name__
        if not hasattr(cls, attr_name):
            setattr(cls, attr_name, weakref.WeakKeyDictionary())
        return getattr(cls, attr_name) 

def _async_clients(cls):
        attr_name = '_async_client_dict_' + cls.__name__
        if not hasattr(cls, attr_name):
            setattr(cls, attr_name, weakref.WeakKeyDictionary())
        return getattr(cls, attr_name) 

def __init__(self, value_type, offset, default, documentation):
        SpecificNamedField = type('SpecificNamedField', (NamedField,), {'__doc__': documentation})
        self._named_field = SpecificNamedField(value_type, offset, default, documentation)
        self._instance_data = WeakKeyDictionary() 

def _type_memos(self):
        return weakref.WeakKeyDictionary() 

def __init__(self, parent_dispatch_cls, fn):
        self.name = fn.__name__
        argspec = util.inspect_getargspec(fn)
        self.arg_names = argspec.args[1:]
        self.has_kw = bool(argspec.keywords)
        self.legacy_signatures = list(reversed(
            sorted(
                getattr(fn, '_legacy_signatures', []),
                key=lambda s: s[0]
            )
        ))
        fn.__doc__ = legacy._augment_fn_docs(self, parent_dispatch_cls, fn)

        self._clslevel = weakref.WeakKeyDictionary() 

def __init__(self):
        self.proxy_refs = weakref.WeakKeyDictionary()
        self.testing_engines = weakref.WeakKeyDictionary()
        self.conns = set() 

def _take_snapshot(self):
        if not self._is_transaction_boundary:
            self._new = self._parent._new
            self._deleted = self._parent._deleted
            self._dirty = self._parent._dirty
            self._key_switches = self._parent._key_switches
            return

        if not self.session._flushing:
            self.session.flush()

        self._new = weakref.WeakKeyDictionary()
        self._deleted = weakref.WeakKeyDictionary()
        self._dirty = weakref.WeakKeyDictionary()
        self._key_switches = weakref.WeakKeyDictionary() 

def __init__(self, area):
        object.__init__(self)
        self.area = area
        self._container = None
        self._stretch = (10, 10)
        self.stretches = weakref.WeakKeyDictionary() 

def __init__(self, widgetList=None):
        """Initialize WidgetGroup, adding specified widgets into this group.
        widgetList can be: 
         - a list of widget specifications (widget, [name], [scale])
         - a dict of name: widget pairs
         - any QObject, and all compatible child widgets will be added recursively.
        
        The 'scale' parameter for each widget allows QSpinBox to display a different value than the value recorded
        in the group state (for example, the program may set a spin box value to 100e-6 and have it displayed as 100 to the user)
        """
        QtCore.QObject.__init__(self)
        self.widgetList = weakref.WeakKeyDictionary() # Make sure widgets don't stick around just because they are listed here
        self.scales = weakref.WeakKeyDictionary()
        self.cache = {}  ## name:value pairs
        self.uncachedWidgets = weakref.WeakKeyDictionary()
        if isinstance(widgetList, QtCore.QObject):
            self.autoAdd(widgetList)
        elif isinstance(widgetList, list):
            for w in widgetList:
                self.addWidget(*w)
        elif isinstance(widgetList, dict):
            for name, w in widgetList.items():
                self.addWidget(w, name)
        elif widgetList is None:
            return
        else:
            raise Exception("Wrong argument type %s" % type(widgetList)) 

def __init__(self, dict=None):
        weakref.WeakKeyDictionary.__init__(self, dict=dict)
        self._result_tileables = []