code: def _run_interface(self, runtime):
      runtime.returncode = 0
      self._results["output1"] = [1, self.inputs.input1]
      return runtime
  
file_path: nipype/nipype/pipeline/engine/tests/test_base.py
imports: import pytest
  from ..base import EngineBase
  from ....interfaces import base
  from ....interfaces import utility
  from ...None import engine
label_desc: Use image node_id 1 for calling the EngineTestInterface obj's underlying member method code with example usage: obj._run_interface(runtime) and returns: runtime