code: def _generate_slices(len_: int):
      """Generates slices ``[{start}:{stop}:{step}]`` with all valid
      combinations of start,stop,step for a list of length ``len_``.
      """
      for x, y in combinations(range(-len_, len_), 2):
          for step in range(1, len_):
              yield slice(x, y, step)
              yield slice(y, x, step)
  
file_path: pennylane/tests/data/attributes/test_list.py
imports: from itertools import combinations
  import pytest
  from pennylane.data import DatasetList
label_desc: Use image node_id 1 for calling a global function with example usage: _generate_slices(len_) without return types