public default <E extends Throwable> V orElseThrow(final Supplier<? extends E> exceptionSupplier) throws E {
        if (this.isPresent()) return this.value();
        else
            throw exceptionSupplier.get();
    }
If the value is present, return the value, else throw the exception generated by the {@link Supplier}.

@param exceptionSupplier The supplier to generate an exception if the property is not present
@param <E>               The exception type
@return A value
@throws E if the property is not present, the exception is thrown
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/Property.java