code: def __next__(self):
      self.idx += 1
      v = next(self.it)
      if self.callback:
          self.callback(v)
          return v
      else:
          return v
  
file_path: labml/client/labml/internal/monitor/mix.py
imports: from typing import Tuple, Union, Callable, Any, List, cast, Sized, TYPE_CHECKING, Iterator
label_desc: Use image node_id 4 for calling the SplitIterator obj's underlying member method code with example usage: obj.__next__() and returns: v, v