docs: public <V> void setColumnValue(T instance, String columnName, V value) {
          Field field = fields.get(columnName);
          if (field == null) {
              throw new IllegalArgumentException("Column not found: "
                      + columnName);
          }
          try {
              field.set(instance, value);
          } catch (IllegalAccessException e) {
              throw new RuntimeException(e); // should never get here
          }
      }