class_docstr: Describes a batch or sub-batch of work in sample mode that consists of SampleInfo
  instances with consecutive indices. It denotes range of samples within given `iteration`
  of given `epoch_idx`, optionally specifying a slice/sub-range of the sample range.
  It does not support spanning over multiple batches. Used to avoid linear dependency of the task
  description size on the batch size.
code: def __len__(self):
      return self.slice_end - self.slice_start
  
imports: from typing import Optional
  from nvidia.dali.types import SampleInfo
  from nvidia.dali._multiproc.struct_message import Structure
label_desc: Use image node_id 5 for calling the SampleRange obj's underlying member method code with example usage: obj.__len__() and returns: unknown