def METHOD_NAME(
    target: np.ndarray,
    lower_quantile: np.ndarray,
    upper_quantile: np.ndarray,
    seasonal_error: float,
    alpha: float,
) -> float:
    r"""
    .. math::
        msis = mean(U - L + 2/alpha * (L-Y) * I[Y<L] + 2/alpha * (Y-U) * I[Y>U]) / seasonal\_error
    See [SSA20]_ for more details.
    """  # noqa: E501
    numerator = np.mean(
        upper_quantile
        - lower_quantile
        + 2.0 / alpha * (lower_quantile - target) * (target < lower_quantile)
        + 2.0 / alpha * (target - upper_quantile) * (target > upper_quantile)
    )
    return numerator / seasonal_error