Function masked_less 

pub fn masked_less<A, S, D>(
    data: ArrayBase<S, D>,
    value: &A,
) -> MaskedArray<A, S, D>
where
    A: Clone + PartialEq + PartialOrd,
    S: Data<Elem = A> + Clone + RawDataClone,
    D: Dimension,

Create a masked array with values less than a given value masked