code: def __len__(self):
      return self._dataset_length
  
file_path: ColossalAI/examples/language/bert/benchmark.py
imports: import argparse
  import torch
  from benchmark_utils import benchmark
  from torch.utils.data import DataLoader, Dataset
  from transformers import AlbertConfig, AlbertForSequenceClassification, BertConfig, BertForSequenceClassification, get_linear_schedule_with_warmup
  import colossalai
  from colossalai.booster import Booster
  from colossalai.booster.plugin import GeminiPlugin, LowLevelZeroPlugin, TorchDDPPlugin
  from colossalai.cluster import DistCoordinator
  from colossalai.nn.optimizer import HybridAdam
label_desc: Use image node_id 2 for calling the RandintDataset obj's underlying member method code with example usage: obj.__len__() and returns: self