code: public List<E> filterCurrentPageBy(String columnName, Serializable filterValue) throws HelloSignException {
          ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();
          @SuppressWarnings("unchecked")
          Class<E> clazz = (Class<E>) genericSuperclass.getActualTypeArguments()[0];
          return getList(clazz, listKey, filterValue, columnName);
      }
docs: Filters the current page of results by the given column and value.
  
  @param columnName String column name to filter by
  @param filterValue Serializable matching value
  @return List results
  @throws HelloSignException thrown if the column name is invalid