Error with handling variable length data (H5T_VLEN) about hdf5.node HOT 6 OPEN

const dims = group.getDatasetDimensions('labels');

var data = h5lt.readDataset(group.id, 'labels');
                ^

SyntaxError: unsupported data type
    at Object.<anonymous> (hdfGenerator.js:23:17)
    at Module._compile (internal/modules/cjs/loader.js:722:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:733:10)
    at Module.load (internal/modules/cjs/loader.js:620:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:560:12)
    at Function.Module._load (internal/modules/cjs/loader.js:552:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:775:12)
    at startup (internal/bootstrap/node.js:300:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:826:3)

import numpy as np
import h5py

label_dtype = np.dtype(
  [('type1', np.float),
   ('type2', np.float),
   ('type3', np.uint8),
   ('type4', np.uint16),
   ('type5', np.uint16)])

with h5py.File('testdata.hdf5', 'a') as hdf:
  if 'real' in hdf:
    del hdf['real']
  
  hdf_group = hdf.create_group('real')
  hdf_labels = hdf_group.create_dataset('labels', (3,), h5py.special_dtype(vlen = label_dtype))
  
  for i in range(3):
    labels = np.empty(i + 1, label_dtype)
    for j in range(i + 1):
      labels[j]['type1'] = j
      labels[j]['type2'] = j + 1
      labels[j]['type3'] = j + 2
      labels[j]['type4'] = j + 3
      labels[j]['type5'] = j + 4
    hdf_labels[i] = labels

HDF5 "testdata.hdf5" {
GROUP "/" {
   GROUP "real" {
      DATASET "labels" {
         DATATYPE  H5T_VLEN { H5T_COMPOUND {
            H5T_IEEE_F64LE "type1";
            H5T_IEEE_F64LE "type2";
            H5T_STD_U8LE "type3";
            H5T_STD_U16LE "type4";
            H5T_STD_U16LE "type5";
         }}
         DATASPACE  SIMPLE { ( 3 ) / ( 3 ) }
         DATA {
         (0): ({
                  0,
                  1,
                  2,
                  3,
                  4
               }),
         (1): ({
                  0,
                  1,
                  2,
                  3,
                  4
               }, {
                  1,
                  2,
                  3,
                  4,
                  5
               }),
         (2): ({
                  0,
                  1,
                  2,
                  3,
                  4
               }, {
                  1,
                  2,
                  3,
                  4,
                  5
               }, {
                  2,
                  3,
                  4,
                  5,
                  6
               })
         }
      }
   }
}
}