class_docstr: Runing statistics for counting tokens before/after subword transform.
code: def __init__(self, subwords: int, words: int):
      self.subwords = subwords
      self.words = words
  
imports: import re
  from onmt.utils.logging import logger
  from onmt.transforms import register_transform
  from .transform import Transform, ObservableStats
  from onmt.constants import DefaultTokens
label_desc: Use image node_id 1 to create a new SubwordStats object from inherited base classes: ObservableStats with example: obj = SubwordStats(subwords, words)