code: def __enter__(self):
      self.src_stream.flush()
      self._old_src_stream = os.dup(self.src_stream.fileno())
      self._old_dst_stream_pos = self.dst_stream.tell()
      os.dup2(self.dst_stream.fileno(), self.src_stream.fileno())
  
imports: import collections
  import csv
  import json
  import os
  import random
  import shutil
  import sys
  from pandas import read_csv, DataFrame
  from copy import deepcopy
  import numpy
  from catboost.utils import read_cd
label_desc: Use image node_id 2 for calling the DelayedTee obj's underlying member method code with example usage: obj.__enter__() without return types