code: def finish_subsegment(writer, k=64):
      # Tell the pool to finish up the current file
      writer.pool.save()
      # Tell the pool to merge any and all runs in the pool until there
      # is only one run remaining. "k" is an optional parameter passed
      # from the parent which sets the maximum number of files to open
      # while reducing.
      writer.pool.reduce_to(1, k)
  
      # The filename of the single remaining run
      runname = writer.pool.runs[0]
      # The indexed field names
      fieldnames = writer.pool.fieldnames
      # The segment object (parent can use this to re-open the files created
      # by the sub-writer)
      segment = writer._partial_segment()
  
      return runname, fieldnames, segment
  
imports: from __future__ import with_statement
  from multiprocessing import Process, Queue, cpu_count
  from whoosh.compat import queue, xrange, pickle
  from whoosh.codec import base
  from whoosh.writing import SegmentWriter
  from whoosh.externalsort import imerge
  from whoosh.util import random_name
label_desc: Use image node_id 1 for calling a global function with example usage: finish_subsegment(writer, k) and returns: runname,  fieldnames,  segment