class_docstr: Abstract iterator object which supports `ready` method.
class_docstr_tok: ["Abstract","iterator","object","which","supports","`","ready","`","method","."]
docstr: How many elements were retrieved from the iterator.
docstr_tok: ["How","many","elements","were","retrieved","from","the","iterator","."]
code: def retrieved_elements(self) -> int:
      """How many elements were retrieved from the iterator."""
  
imports: import abc
  import itertools
  from typing import Generic, Iterator, List, Optional, Sequence, TypeVar
  from acme import types
  from acme.utils import metrics
  import dm_env
label_desc: Use image node_id 2 for calling the PrefetchingIterator obj's underlying member method code with example usage: obj.retrieved_elements() without return types