presto-spi/src/main/java/io/prestosql/spi/predicate/ValueSet.java/ValueSet/union
class ValueSet:    default ValueSet union(Collection<ValueSet> valueSets)
    {
        ValueSet current = this;
        for (ValueSet valueSet : valueSets) {
            current = current.union(valueSet);
        }
        return current;
    }