class_docstr: Wrap a sequence of (func, args, kwargs) tuples as a single callable
code: def __len__(self):
      return self._size
  
imports: from __future__ import division
  import os
  import sys
  from math import sqrt
  import functools
  import time
  import threading
  import itertools
  from numbers import Integral
  from contextlib import contextmanager
  from ._multiprocessing_helpers import mp
  from .format_stack import format_outer_frames
  from .logger import Logger, short_format_time
  from .my_exceptions import TransportableException, _mk_exception
  from .disk import memstr_to_bytes
  from ._parallel_backends import FallbackToBackend, MultiprocessingBackend, ThreadingBackend, SequentialBackend
  from ._compat import _basestring
  from .func_inspect import getfullargspec
  from ._parallel_backends import AutoBatchingMixin
  from ._parallel_backends import ParallelBackendBase
label_desc: Use image node_id 3 for calling the BatchedCalls obj's underlying member method code with example usage: obj.__len__() and returns: self