code: def prefetch(self, indices):
      for ds in self.datasets:
          if getattr(ds, "supports_prefetch", False):
              ds.prefetch(indices)
  
file_path: fairseq/fairseq/data/concat_sentences_dataset.py
imports: import torch
  from .None import FairseqDataset
label_desc: Use image node_id 10 for calling the ConcatSentencesDataset obj's underlying member method code with example usage: obj.prefetch(indices) without return types