code: def disable_pruned_instances(self, pruned_mask):
      if len(pruned_mask) != len(self.instances):
          raise RuntimeError(
              f"Mask of the pruned outputs of the external source must have the length matching "
              f"the number of outputs of the external source. The external source node has "
              f"{len(self.instances)} outputs, but received mask of length {len(pruned_mask)}."
          )
      self.utilized_instances = [
          instance
          for instance, is_pruned in zip(self.instances, pruned_mask)
          if not is_pruned
      ]
  
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 3 for calling the _ExternalSourceGroup obj's underlying member method code with example usage: obj.disable_pruned_instances(pruned_mask) without return types