class_docstr: A ParallelBackend which will execute all batches sequentially.
  
  Does not use/create any threading objects, and hence has minimal
  overhead. Used when n_jobs == 1.
class_docstr_tok: ["A","ParallelBackend","which","will","execute","all","batches","sequentially",".","Does","not","use\/create","any","threading","objects",",","and","hence","has","minimal","overhead",".","Used","when","n_jobs","==","1","."]
docstr: Determine the number of jobs which are going to run in parallel
code: def effective_n_jobs(self, n_jobs):
      """Determine the number of jobs which are going to run in parallel"""
      if n_jobs == 0:
          raise ValueError("n_jobs == 0 in Parallel has no meaning")
      return 1
  
imports: import gc
  import os
  import sys
  import warnings
  import threading
  from abc import ABCMeta, abstractmethod
  from .format_stack import format_exc
  from .my_exceptions import WorkerInterrupt, TransportableException
  from ._multiprocessing_helpers import mp
  from ._compat import with_metaclass
label_desc: Use image node_id 1 for calling the SequentialBackend obj's underlying member method code with example usage: obj.effective_n_jobs(n_jobs) and returns: int