code: def specification(self) -> problem.ProblemSpec:
      params = [
          problem.Var(f"x{i}", problem.CategoricalRange(op_names))
          for i in range(edge_num)
      ]
      return problem.ProblemSpec(
          name=f"NASBench201-{self._dataset}",
          params=params,
          values=[problem.Var("value")],
          steps=list(
              range(prune_start_epoch, max_epoch, prune_epoch_step)
          )
          + [max_epoch],
      )
  
file_path: optuna/benchmarks/naslib/problem.py
imports: from __future__ import annotations
  import sys
  from typing import Any
  from kurobako import problem
  from naslib.utils import get_dataset_api
label_desc: Use image node_id 2 for calling the NASLibProblemFactory obj's underlying member method code with example usage: obj.specification() and returns: problem