Function ewm_mean

pub fn ewm_mean<I, T>(
    xs: I,
    alpha: T,
    adjust: bool,
    min_periods: usize,
    ignore_nulls: bool,
) -> PrimitiveArray<T>
where
    I: IntoIterator<Item = Option<T>>,
    I::IntoIter: TrustedLen,
    T: Float + NativeType + AddAssign + MulAssign,