code: public static Set<BioPAXElement> runCommonStreamWithPOI(
  		Set<BioPAXElement> sourceSet,
  		Model model,
  		Direction direction,
  		int limit,
  		Filter... filters)
  	{
  		Graph graph;
  
  		if (model.getLevel() == BioPAXLevel.L3)
  		{
  			graph = new GraphL3(model, filters);
  		}
  		else return Collections.emptySet();
  
  		Collection<Set<Node>> sourceSets = prepareNodeSets(sourceSet, graph);
  
  		if (sourceSet.size() < 2) return Collections.emptySet();
  
  		return runCommonStreamWithPOIContinued(sourceSets, direction, limit, graph);
  	}
docs: First finds the common stream, then completes it with the paths between seed and common
  stream.
  @param sourceSet Seed to the query
  @param model BioPAX model
  @param direction UPSTREAM or DOWNSTREAM
  @param limit Length limit for the search
  @param filters for filtering graph elements
  @return BioPAX elements in the result