public default <E2> Traversal.Admin<S, E2> addStep(final Step<?, E2> step) throws IllegalStateException {
            return this.addStep(this.getSteps().size(), step);
        }
Add a {@link Step} to the end of the traversal. This method should link the step to its next and previous step accordingly.

@param step the step to add
@param <E2> the output of the step
@return the updated traversal
@throws IllegalStateException if the {@link TraversalStrategies} have already been applied
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/Traversal.java