code: def input_size(self) -> int:
      return len(self.variable_names)
  
imports: from typing import Dict, List, Optional, Tuple, Union
  import torch
  import torch.nn
  import torch.nn.functional
  from darts.logging import get_logger
  from darts.utils.torch import MonteCarloDropout
label_desc: Use image node_id 2 for calling the _MultiEmbedding obj's underlying member method code with example usage: obj.input_size() and returns: len