docstr: Number of samples & chunks (e.g., 32*n_samples) in corpus.
docstr_tok: ["Number","of","samples","&","chunks","(","e.g.",",","32","*","n_samples",")","in","corpus","."]
code: def get_pt_num_samples_and_chunks(cls, data_key):
      """Number of samples & chunks (e.g., 32*n_samples) in corpus."""
      assert hasattr(
          cls.pt_datasets, data_key
      ), "pretraining set '%s' not found (choices: %s)." % (
          data_key,
          ", ".join(vars(cls.pt_datasets).keys()),
      )
      chunk_dataset = getattr(cls.pt_datasets, data_key).chunk_dataset
      return (
          len(chunk_dataset.sample_dataset),
          len(chunk_dataset),
      )
  
imports: import json
  import numpy
  import os
  import torch
  import types
  from megatron.global_vars import set_global_variables, set_retro_args
  from megatron.initialize import initialize_megatron, _initialize_distributed, _set_random_seed, _compile_dependencies
  from tools.retro.db.utils import get_indexed_dataset_infos, get_merged_train_dataset
  from tools.retro.main import add_retro_args
  from tools.retro.query.retro_dataset import get_retro_datasets
  from tools.retro.utils import get_args_path, get_bert_tokenizer, get_gpt_tokenizer
label_desc: Use image node_id 14 for calling the retro obj's underlying member method code with example usage: obj.get_pt_num_samples_and_chunks(cls, data_key) and returns: len,  len