code: @Deprecated
      public void fillFields(Entity entity) {
          for (Field field : entity.getAllFields()) {
              if (!containsField(field.getId())) {
                  getFields().add(field);
              }
          }
      }
docs: This method fills the extendsFields variable with the parent Fields. If
  some field is redefined, parent field is ignored
  
  @param entity The parent entity given by PM engine