true if the two items are approximately equal under either criterium.
It is sufficient, when value satisfies one of the two criteria.
If one item is a range, and the other is a single value, then the result is the logical and-ing of calling isClose on each element of the ranged item against the single item. If both items are ranges, then isClose returns true if and only if the ranges have the same number of elements and if isClose evaluates to true for each pair of elements.