code: def preserve(self):
      return self._preserve
  
imports: import nvidia.dali.python_function_plugin
  from nvidia.dali import backend
  from nvidia.dali import ops
  from nvidia.dali.ops import _registry
  from nvidia.dali.data_node import DataNode
  from nvidia.dali.pipeline import Pipeline
  from nvidia.dali.types import CUDAStream
label_desc: Use image node_id 5 for calling the PythonFunctionBase obj's underlying member method code with example usage: obj.preserve() and returns: self