class_docstr: Runing statistics for counting tokens being switched out.
code: def update(self, other: "TokenMaskStats"):
      self.masked += other.masked
      self.total += other.total
  
imports: import random
  import numpy
  from onmt.constants import DefaultTokens
  from onmt.transforms import register_transform
  from .transform import Transform, ObservableStats
label_desc: Use image node_id 2 for calling the TokenMaskStats obj's underlying member method code with example usage: obj.update(other) without return types