code: def __init__(self, repr):
      assert isinstance(repr, str)
      self.repr = repr
  
imports: import sys
  import warnings
  from IPython.core import ultratb, compilerop
  from IPython.core import magic_arguments
  from IPython.core.magic import Magics, magics_class, line_magic
  from IPython.core.interactiveshell import DummyMod, InteractiveShell
  from IPython.terminal.interactiveshell import TerminalInteractiveShell
  from IPython.terminal.ipapp import load_default_config
  from traitlets import Bool, CBool, Unicode
  from IPython.utils.io import ask_yes_no
  from typing import Set
label_desc: Use image node_id 1 to create a new _Sentinel object  with example: obj = _Sentinel(repr)