class_docstr: Describes the indices of a sample requested from :meth:`nvidia.dali.fn.external_source`
  
  :ivar idx_in_epoch: 0-based index of the sample within epoch
  :ivar idx_in_batch: 0-based index of the sample within batch
  :ivar iteration:    number of current batch within epoch
  :ivar epoch_idx:    number of current epoch
class_docstr_tok: ["Describes","the","indices","of","a","sample","requested","from",":","meth",":","`","nvidia.dali.fn.external_source","`",":","ivar","idx_in_epoch",":","0-based","index","of","the","sample","within","epoch",":","ivar","idx_in_batch",":","0-based","index","of","the","sample","within","batch",":","ivar","iteration",":","number","of","current","batch","within","epoch",":","ivar","epoch_idx",":","number","of","current","epoch"]
code: def __init__(self, idx_in_epoch, idx_in_batch, iteration, epoch_idx):
      self.idx_in_epoch = idx_in_epoch
      self.idx_in_batch = idx_in_batch
      self.iteration = iteration
      self.epoch_idx = epoch_idx
  
imports: from enum import Enum, unique
  import re
  from nvidia.dali._backend_enums import DALIDataType, DALIImageType, DALIInterpType
  from nvidia.dali.backend_impl.types import *
label_desc: Use image node_id 1 to create a new SampleInfo object  with example: obj = SampleInfo(idx_in_epoch, idx_in_batch, iteration, epoch_idx)