code: def _execute_operand(self, ctx: Dict[str, Any], op: OperandType):
      super()._execute_operand(ctx, op)
      if self._check_options.get("check_all", True):
          for out in op.outputs:
              if out not in self._chunk_graph.result_chunks:
                  continue
              if self._check_keys and out.key not in self._check_keys:
                  continue
              # The first char of key is a letter.
              assert out.key[0] in {"c", "d", "e", "f"}, out.key
              if out.key not in ctx and any(
                  k[0] == out.key for k in ctx if isinstance(k, tuple)
              ):
                  # both shuffle mapper and reducer
                  continue
              self.assert_object_consistent(out, ctx[out.key])
  
file_path: mars/mars/services/subtask/worker/tests/subtask_processor.py
imports: from typing import Any, Dict
  from .....core import OperandType
  from .....tests.core import _check_args, ObjectCheckMixin
  from ...worker.processor import SubtaskProcessor
label_desc: Use image node_id 2 for calling the CheckedSubtaskProcessor obj's underlying member method code with example usage: obj._execute_operand(ctx, op) without return types