code: def __call__(self, x, x_lens):
      x, _ = self.pre_rnn(x, None)
      x, x_lens = self.stack_time(x, x_lens)
      x, _ = self.post_rnn(x, None)
      return x.transpose(0, 1), x_lens
  
imports: from tinygrad.tensor import Tensor
  from tinygrad.jit import TinyJit
  from tinygrad.nn import Linear, Embedding
  from tinygrad.helpers import fetch
  import numpy
  from pathlib import Path
label_desc: Use image node_id 2 for calling the Encoder obj's underlying member method code with example usage: obj.__call__(x, x_lens) and returns: x,  x_lens