code: def reset_indices(self):
      self.current_iter = 0
      self.current_sample = 0
  
imports: from nvidia.dali import backend
  from nvidia.dali import tensors
  from nvidia.dali import types
  from nvidia.dali._multiproc.messages import TaskArgs, SampleRange
  import nvidia.dali.types
  from nvidia.dali._utils.external_source_impl import get_callback_from_source, accepted_arg_count, SourceKind
label_desc: Use image node_id 5 for calling the _ExternalSourceGroup obj's underlying member method code with example usage: obj.reset_indices() without return types