class_docstr: Dataset for test data in WikiKG90M
  
  Args:
      triplets (dict):
          The collection of test data with keys 'h', 'r',
          'candidate_t', 't_correct_index'.
          The values of 'h', 'r' and 't_correct_index' are 1D np.ndarray.
          The values of 'candidate_t' are 2D np.ndarray.
class_docstr_tok: ["Dataset","for","test","data","in","WikiKG90M","Args",":","triplets","(","dict",")",":","The","collection","of","test","data","with","keys","'","h","'",",","'","r","'",",","'candidate_t","'",",","'t_correct_index","'",".","The","values","of","'","h","'",",","'","r","'","and","'t_correct_index","'","are","1D","np.ndarray",".","The","values","of","'candidate_t","'","are","2D","np.ndarray","."]
code: def __getitem__(self, index):
      h = self._h[index]
      r = self._r[index]
      neg_tail = self._candidate[index]
      if self._t_index is not None:
          t = self._t_index[index]
          return h, r, t, neg_tail
      else:
          return h, r, -1, neg_tail
  
imports: import os
  import numpy
  from numpy.random import default_rng
  import paddle
  from paddle.io import Dataset
  from paddle.io import DataLoader, DistributedBatchSampler
  from utils import timer_wrapper
label_desc: Use image node_id 3 for calling the TestWikiKG90M obj's underlying member method code with example usage: obj.__getitem__(index) and returns: h,  r,  t,  neg_tail, h,  r,  unknown,  neg_tail