code: public synchronized Set<Evidence> getEvidence(EvidenceType type) {
          if (null != type) {
              switch (type) {
                  case VENDOR:
                      return Collections.unmodifiableSet(new HashSet<>(vendors));
                  case PRODUCT:
                      return Collections.unmodifiableSet(new HashSet<>(products));
                  case VERSION:
                      return Collections.unmodifiableSet(new HashSet<>(versions));
                  default:
                      break;
              }
          }
          return null;
      }
docs: Returns the unmodifiable set of evidence of the given type.
  
  @param type the type of evidence (vendor, product, version)
  @return the unmodifiable set of evidence