code: def num_features(self) -> int:
      return len(self.feature_names)
  
imports: from dataclasses import dataclass, field
  from enum import Enum, unique
  from functools import partial
  from math import sqrt
  from typing import Callable, Dict, List, NamedTuple, Optional
  import torch
  from fbgemm_gpu.split_embedding_configs import SparseType
  from fbgemm_gpu.split_table_batched_embeddings_ops_training import PoolingMode
  from torchrec.types import DataType
label_desc: Use image node_id 3 for calling the BaseEmbeddingConfig obj's underlying member method code with example usage: obj.num_features() and returns: len