docstr: Number of tokens in the sequence that have completed a forward pass.
docstr_tok: ["Number","of","tokens","in","the","sequence","that","have","completed","a","forward","pass","."]
code: def seen_tokens(self) -> int:
      """
      Number of tokens in the sequence that have completed a forward pass.
      """
      return self._seen_tokens
  
imports: from typing import List, Tuple, Union
  import torch
label_desc: Use image node_id 2 for calling the DSSequenceDescriptor obj's underlying member method code with example usage: obj.seen_tokens() and returns: self