Method increment

src/main/java/groovy/lang/NumberRange.java:761–764

Increments by given step @param value the value to increment @param step the amount to increment @return the incremented value

(Object value, Number step)

     * @return the incremented value
     */
    @SuppressWarnings("unchecked")
    private Comparable increment(Object value, Number step) {
        return (Comparable) plus((Number) value, step);
    }

    /**
     * Decrements by given step