code: def test_empty_commit():
      s = fields.Schema(id=fields.ID(stored=True))
      with TempIndex(s, "emptycommit") as ix:
          w = ix.writer()
          w.add_document(id=u("1"))
          w.add_document(id=u("2"))
          w.add_document(id=u("3"))
          w.commit()
  
          w = ix.writer()
          w.commit()
  
imports: from __future__ import with_statement
  import random
  from collections import defaultdict
  from datetime import datetime
  import pytest
  from whoosh import analysis, fields, index, qparser, query, __version__
  from whoosh.compat import b, u, xrange, text_type, permutations
  from whoosh.filedb.filestore import RamStorage
  from whoosh.writing import IndexingError
  from whoosh.util.numeric import length_to_byte, byte_to_length
  from whoosh.util.testing import TempIndex, TempStorage
label_desc: Use image node_id 2 for calling a global function with example usage: test_empty_commit() without return types