public static Months ofYears(int years) {
        if (years == 0) {
            return ZERO;
        }
        return new Months(Math.multiplyExact(years, MONTHS_PER_YEAR));
    }
public static Months ofYears ( int years ) { if ( years == 0 ) { return ZERO ; } return new Months ( Math . multiplyExact ( years , MONTHS_PER_YEAR ) ) ; }
Obtains a {@code Months} representing the number of months
equivalent to a number of years.
<p>
The resulting amount will be month-based, with the number of months
equal to the number of years multiplied by 12.

@param years  the number of years, positive or negative
@return the amount with the input years converted to months, not null
@throws ArithmeticException if numeric overflow occurs