A Deque subclass that maintains a running sum of it's values

running_sum_deque.py

from typing import Deque, Iterable

T = float


class RunningSumDeque(Deque[T]):
    def __init__(self, iterable: Iterable[T], maxlen: int):
        super().__init__(iterable, maxlen)
        self.__sum = sum(self)

    @property
    def sum(self) -> T:
        return self.__sum

    @property
    def mean(self) -> T:
        return self.__sum / len(self)

    def append(self, x: T) -> None:
        if len(self) == self.maxlen:
            self.__sum -= self[0]
        self.__sum += x
        super().append(x)

    def appendleft(self, x: T) -> None:
        if len(self) == self.maxlen:
            self.__sum -= self[-1]
        self.__sum += x
        super().appendleft(x)

    def clear(self) -> None:
        super().clear()
        self.__sum = 0

    def insert(self, i: int, x: T) -> None:
        super().insert(i, x)
        self.__sum += x

    def pop(self):
        value = super().pop()
        self.__sum -= value
        return value

    def popleft(self) -> T:
        value = super().popleft()
        self.__sum -= value
        return value

    def remove(self, value):
        super().remove(value)
        self.__sum -= value