code: def compute_output_spec(self, x):
      axis = self.axis
      if axis < 0:
          axis = len(x.shape) + axis
      output_shapes = x.shape[:axis] + x.shape[axis + 1 :]
      num = self.num
      if num is None:
          num = x.shape[axis]
      if num is None:
          raise ValueError(
              "Cannot infer argument `num` from shape "
              f"{x.shape}. Either provide a tensor with a "
              "concrete shape in the `axis` dimension or "
              "explicitly pass the `num` argument."
          )
      output = [
          KerasTensor(shape=output_shapes, dtype=x.dtype)
          for _ in range(num)
      ]
      return output
  
imports: import numpy
  from keras import backend
  from keras.api_export import keras_export
  from keras.backend import KerasTensor
  from keras.backend import any_symbolic_tensors
  from keras.ops.operation import Operation
  from keras.utils import traceback_utils
label_desc: Use image node_id 3 for calling the Unstack obj's underlying member method code with example usage: obj.compute_output_spec(x) and returns: output