code: def FrameStackMLP(
      n_frames=4, hidden_sizes=(64,), output_size=64, mode="train"
  ):
      """MLP operating on a fixed number of last frames."""
      del mode
  
      return tl.Serial(
          _FrameStack(n_frames=n_frames),
          [
              [tl.Dense(d_hidden), tl.Relu()]
              for d_hidden in hidden_sizes
          ],
          tl.Dense(output_size),
      )
  
imports: from trax import layers
label_desc: Use image node_id 5 for calling a global function with example usage: FrameStackMLP(n_frames, hidden_sizes, output_size, mode) and returns: tl