code: def __len__(self):
      return self.x.size(0)
  
file_path: ogb/examples/nodeproppred/papers100M/mlp.py
imports: import argparse
  from tqdm.auto import tqdm
  import torch
  import torch.nn.functional
  from torch.utils.data import Dataset, DataLoader
  from ogb.nodeproppred import Evaluator
  from logger import Logger
label_desc: Use image node_id 2 for calling the SimpleDataset obj's underlying member method code with example usage: obj.__len__() and returns: self