code: public FloatWritable getValueFloatWritable(String label) {
          HadoopObject o = getHadoopObject(VALUE, label, ObjectUtil.FLOAT, "Float");
          if (o == null) {
              return null;
          }
          return (FloatWritable) o.getObject();
      }
docs: Get value {@link FloatWritable} value
  @param label target label
  @return {@link FloatWritable} value of the label. If it is not null.