code: public void insertAttributeAt(Attribute attribute, int i) {
          this.attributesInformation.insertAttributeAt(attribute,i) ;
          if (this.classIndex >= i) {
              this.classIndex++;
          }
      }
docs: /* (non-Javadoc)
  @see com.yahoo.labs.samoa.instances.InstanceInformationInterface#insertAttributeAt(com.yahoo.labs.samoa.instances.Attribute, int)