code: public List<TopicRelationship> getPrevTopicRelationships() {
          ArrayList<TopicRelationship> relationships = new ArrayList<TopicRelationship>();
          for (TopicRelationship relationship : topicRelationships) {
              if (relationship.getType() == RelationshipType.PREVIOUS) {
                  relationships.add(relationship);
              }
          }
          for (TargetRelationship relationship : topicTargetRelationships) {
              if (relationship.getType() == RelationshipType.PREVIOUS) {
                  relationships.add(new TopicRelationship(relationship.getPrimaryRelationship(), (SpecTopic) relationship.getSecondaryRelationship(),
                          relationship.getType()));
              }
          }
          return relationships;
      }
docs: Gets the list of Topic Relationships for this topic whose type is "PREVIOUS".
  
  @return A list of previous topic relationships