options = none block inline inline-block table table-cell table-row flex inline-flex;

write-display(value) {
    if value == flex {
        flexbox(flex, !important);
    }
    else if value == inline-flex {
        flexbox(inline-flex, !important);
    }
    else {
        display: value !important;
    }
}
.u-display {
    for value in options {
        &--{value} {
            write-display(value);
        }
    }

    for bp in sm md lg xl {
        @media (min-width: lookup('$screen--' + bp)) {
            for value in options {
                &--{value}\\@{bp} {
                    write-display(value);
                }
            }
        }
    }
}