code: def call(self, context, x, losses=None):
      
      has_length_dim = context.length_dim in x.shape.dims
      if not has_length_dim:
        x_shape = x.shape
        shape_with_length = mtf.Shape(
            x_shape.dims[:-1] + [mtf.Dimension("length", 1)]
            + x_shape.dims[-1:])
        x = mtf.reshape(x, shape_with_length)
      y, loss = transformer_moe_layer_v2(
          x,
          context.model_dim,
          self._hparams,
          context.train,
          context.variable_dtype,
          layout=context.layout,
          mesh_shape=context.mesh_shape,
          nonpadding=context.nonpadding)
      if context.losses is not None:
        context.losses.append(loss)
      if not has_length_dim:
        y = mtf.reshape(y, x_shape)
      return y
docs: Call the layer.