docs: public List<GroovyClassDoc> getParentClasses() {
          List<GroovyClassDoc> result = new LinkedList<GroovyClassDoc>();
          if (isInterface()) return result;
          result.add(0, this);
          GroovyClassDoc next = this;
          while (next.superclass() != null && !"java.lang.Object".equals(next.qualifiedTypeName())) {
              next = next.superclass();
              result.add(0, next);
          }
          GroovyClassDoc prev = next;
          Class nextClass = getClassOf(next.qualifiedTypeName());
          while (nextClass != null && nextClass.getSuperclass() != null && !Object.class.equals(nextClass)) {
              nextClass = nextClass.getSuperclass();
              GroovyClassDoc nextDoc = new ExternalGroovyClassDoc(nextClass);
              if (prev instanceof SimpleGroovyClassDoc) {
                  SimpleGroovyClassDoc parent = (SimpleGroovyClassDoc) prev;
                  parent.setSuperClass(nextDoc);
              }
              result.add(0, nextDoc);
              prev = nextDoc;
          }
          if (!result.get(0).qualifiedTypeName().equals("java.lang.Object")) {
              result.add(0, new ExternalGroovyClassDoc(Object.class));
          }
          return result;
      }