How to use the pyrsistent._pdeque.PDeque function in pyrsistent

def extend(self, iterable):
        """
        Return new deque with all elements of iterable appended to the right.

        >>> pdeque([1, 2]).extend([3, 4])
        pdeque([1, 2, 3, 4])
        """
        new_right_list, new_left_list, extend_count = self._extend(self._right_list, self._left_list, iterable)
        return PDeque(new_left_list, new_right_list, self._length + extend_count, self._maxlen)

def __new__(cls, left_list, right_list, length, maxlen=None):
        instance = super(PDeque, cls).__new__(cls)
        instance._left_list = left_list
        instance._right_list = right_list
        instance._length = length

        if maxlen is not None:
            if not isinstance(maxlen, Integral):
                raise TypeError('An integer is required as maxlen')

            if maxlen < 0:
                raise ValueError("maxlen must be non-negative")

        instance._maxlen = maxlen
        return instance

def reverse(self):
        """
        Return reversed deque.

        >>> pdeque([1, 2, 3]).reverse()
        pdeque([3, 2, 1])

        Also supports the standard python reverse function.

        >>> reversed(pdeque([1, 2, 3]))
        pdeque([3, 2, 1])
        """
        return PDeque(self._right_list, self._left_list, self._length)
    __reversed__ = reverse

def popleft(self, count=1):
        """
        Return new deque with leftmost element removed. Otherwise functionally
        equivalent to pop().

        >>> pdeque([1, 2]).popleft()
        pdeque([2])
        """
        if count < 0:
            return self.pop(-count)

        new_left_list, new_right_list = PDeque._pop_lists(self._left_list, self._right_list, count)
        return PDeque(new_left_list, new_right_list, max(self._length - count, 0), self._maxlen)

will return the empty queue. A optional count can be given to indicate the
        number of elements to pop. Popping with a negative index is the same as
        popleft. Executes in amortized O(k) where k is the number of elements to pop.

        >>> pdeque([1, 2]).pop()
        pdeque([1])
        >>> pdeque([1, 2]).pop(2)
        pdeque([])
        >>> pdeque([1, 2]).pop(-1)
        pdeque([2])
        """
        if count < 0:
            return self.popleft(-count)

        new_right_list, new_left_list = PDeque._pop_lists(self._right_list, self._left_list, count)
        return PDeque(new_left_list, new_right_list, max(self._length - count, 0), self._maxlen)

def appendleft(self, elem):
        """
        Return new deque with elem as the leftmost element.

        >>> pdeque([1, 2]).appendleft(3)
        pdeque([3, 1, 2])
        """
        new_right_list, new_left_list, new_length = self._append(self._right_list, self._left_list, elem)
        return PDeque(new_left_list, new_right_list, new_length, self._maxlen)

def left(self):
        """
        Leftmost element in dqueue.
        """
        return PDeque._tip_from_lists(self._left_list, self._right_list)

raise TypeError("'%s' object cannot be interpreted as an index" % type(index).__name__)

        if index >= 0:
            return self.popleft(index).left

        shifted = len(self) + index
        if shifted < 0:
            raise IndexError(
                "pdeque index {0} out of range {1}".format(index, len(self)),
            )
        return self.popleft(shifted).left

    index = Sequence.index

Sequence.register(PDeque)
Hashable.register(PDeque)


def pdeque(iterable=(), maxlen=None):
    """
    Return deque containing the elements of iterable. If maxlen is specified then
    len(iterable) - maxlen elements are discarded from the left to if len(iterable) > maxlen.

    >>> pdeque([1, 2, 3])
    pdeque([1, 2, 3])
    >>> pdeque([1, 2, 3, 4], maxlen=2)
    pdeque([3, 4], maxlen=2)
    """
    t = tuple(iterable)
    if maxlen is not None:
        t = t[-maxlen:]
    length = len(t)

if not isinstance(index, Integral):
            raise TypeError("'%s' object cannot be interpreted as an index" % type(index).__name__)

        if index >= 0:
            return self.popleft(index).left

        shifted = len(self) + index
        if shifted < 0:
            raise IndexError(
                "pdeque index {0} out of range {1}".format(index, len(self)),
            )
        return self.popleft(shifted).left

    index = Sequence.index

Sequence.register(PDeque)
Hashable.register(PDeque)


def pdeque(iterable=(), maxlen=None):
    """
    Return deque containing the elements of iterable. If maxlen is specified then
    len(iterable) - maxlen elements are discarded from the left to if len(iterable) > maxlen.

    >>> pdeque([1, 2, 3])
    pdeque([1, 2, 3])
    >>> pdeque([1, 2, 3, 4], maxlen=2)
    pdeque([3, 4], maxlen=2)
    """
    t = tuple(iterable)
    if maxlen is not None:
        t = t[-maxlen:]