The boolean parity function with respect to $N \in 1, 2, 3, \ldots$ is the D218: Boolean function \begin{equation} \{ 0, 1 \}^N \to \{ 0, 1 \}, \quad x \mapsto I_{2 \mathbb{Z} + 1} \left( \sum_{n = 1}^N x_n \right) \end{equation}