code: def test_index_stats(batch_size):
      ndim = 8
      index = Index(ndim=ndim, multi=False)
      keys = np.arange(batch_size)
      vectors = random_vectors(count=batch_size, ndim=ndim)
      index.add(keys, vectors, threads=threads)
  
      assert index.max_level >= 0
      assert index.stats.nodes >= batch_size
      assert index.levels_stats[0].nodes == batch_size
      assert index.level_stats(0).nodes == batch_size
  
      assert index.levels_stats[index.max_level].nodes > 0
  
file_path: usearch/python/scripts/test_index.py
imports: import os
  import pytest
  import numpy
  from usearch.io import load_matrix, save_matrix
  from usearch.eval import random_vectors
  from usearch.index import search
  from usearch.index import Index, MetricKind, ScalarKind, Match, Matches, BatchMatches, Clustering
  from usearch.index import DEFAULT_CONNECTIVITY
label_desc: Use image node_id 5 for calling a global function with example usage: test_index_stats(batch_size) without return types