code: def __iter__(self) -> t.Iterator[V]:
      if not self.entered:
          raise RuntimeError(
              "You need to use progress bars in a with block."
          )
      self.render_progress()
      return self.generator()
  
imports: import contextlib
  import math
  import os
  import sys
  import time
  import typing
  from gettext import gettext
  from io import StringIO
  from types import TracebackType
  from ._compat import _default_text_stdout
  from ._compat import CYGWIN
  from ._compat import get_best_encoding
  from ._compat import isatty
  from ._compat import open_stream
  from ._compat import strip_ansi
  from ._compat import term_len
  from ._compat import WIN
  from .exceptions import ClickException
  from .utils import echo
label_desc: Use image node_id 4 for calling the ProgressBar obj's underlying member method code with example usage: obj.__iter__() and returns: self