code: def test_get_next_candidates_invalid():
      # Give a tree as input and check that for a query, validity flag is 0
      hash_dict, dist_func = initialize_for_bktree()
      bk = BKTree(hash_dict, dist_func)
      assert bk.ROOT == "a"
      query = "5"
      _, validity, _ = bk._get_next_candidates(
          query, bk.dict_all[bk.ROOT], tolerance=1
      )
      assert not validity
  
file_path: imagededup/tests/test_bktree.py
imports: from collections import OrderedDict
  from imagededup.methods.hashing import Hashing
  from imagededup.handlers.search.bktree import BKTree, BkTreeNode
label_desc: Use image node_id 13 for calling a global function with example usage: test_get_next_candidates_invalid() without return types