code: def _ar_highway(self, F, x: Tensor, observed: Tensor) -> Tensor:
      ar_x = F.slice_axis(
          x, axis=2, begin=-self.ar_window, end=None
      )  # NCT
      ar_observed = F.slice_axis(
          observed, axis=2, begin=-self.ar_window, end=None
      )  # NCT
      ar_fc_inputs = F.concat(ar_x, ar_observed, dim=-1)
      ar = self.ar_fc(ar_fc_inputs)  # NxCx(1 or prediction_length)
      return ar
  
imports: from typing import Optional, Type
  import mxnet
  from mxnet.gluon import loss, nn
  from gluonts.core.component import validated
  from gluonts.mx import Tensor
  from gluonts.mx.block.scaler import MeanScaler, NOPScaler
label_desc: Use image node_id 4 for calling the LSTNetBase obj's underlying member method code with example usage: obj._ar_highway(F, x, observed) and returns: ar