public default <A> A sideEffects(final String sideEffectKey) throws IllegalArgumentException {
        return this.asAdmin().getSideEffects().<A>get(sideEffectKey);
    }
Get a particular value from the side-effects of the traverser (thus, traversal).

@param sideEffectKey the key of the value to get from the sideEffects
@param <A>           the type of the returned object
@return the object in the sideEffects of the respective key
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/Traverser.java