code: def forward(
      self, x: Union[np.ndarray, torch.Tensor, Dict[str, torch.Tensor]]
  ) -> torch.Tensor:
      if self.input_layer is not None:
          x = self.input_layer(x)
      return self.mlp(x)
  
file_path: alibi-detect/alibi_detect/cd/pytorch/preprocess.py
imports: from typing import Callable, Dict, Optional, Type, Union
  import numpy
  import torch
  import torch.nn
  from alibi_detect.utils.pytorch.prediction import predict_batch, predict_batch_transformer
  from alibi_detect.utils._types import TorchDeviceType
label_desc: Use image node_id 2 for calling the _Encoder obj's underlying member method code with example usage: obj.forward(x) and returns: self