code: def test_overlapping_lists():
      schema = fields.Schema(id=fields.STORED, tags=fields.KEYWORD)
      ix = RamStorage().create_index(schema)
      with ix.writer() as w:
          w.add_document(id=0, tags=u("alfa bravo charlie"))
          w.add_document(id=1, tags=u("bravo charlie delta"))
          w.add_document(id=2, tags=u("charlie delta echo"))
          w.add_document(id=3, tags=u("delta echo alfa"))
          w.add_document(id=4, tags=u("echo alfa bravo"))
  
      with ix.searcher() as s:
          of = sorting.FieldFacet("tags", allow_overlap=True)
          cat = of.categorizer(s)
          assert not cat._use_vectors
  
          r = s.search(query.Every(), groupedby={"tags": of})
          assert r.groups("tags") == {
              "alfa": [0, 3, 4],
              "bravo": [0, 1, 4],
              "charlie": [0, 1, 2],
              "delta": [1, 2, 3],
              "echo": [2, 3, 4],
          }
  
          fcts = sorting.Facets()
          fcts.add_field("tags", allow_overlap=True)
          r = s.search(query.Every(), groupedby=fcts)
          assert r.groups("tags") == {
              "alfa": [0, 3, 4],
              "bravo": [0, 1, 4],
              "charlie": [0, 1, 2],
              "delta": [1, 2, 3],
              "echo": [2, 3, 4],
          }
  
imports: from __future__ import with_statement
  from datetime import datetime, timedelta
  import random
  from whoosh import fields, query, sorting, columns
  from whoosh.compat import u
  from whoosh.compat import permutations, xrange
  from whoosh.filedb.filestore import RamStorage
  from whoosh.util.testing import TempIndex
label_desc: Use image node_id 24 for calling a global function with example usage: test_overlapping_lists() without return types