code: def test_unbuild_with_loaded_tree():
      i = AnnoyIndex(10, "angular")
      i.load("test/test.tree")
      with pytest.raises(Exception):
          i.unbuild()
  
imports: import os
  import random
  import pytest
  from annoy import AnnoyIndex
label_desc: Use image node_id 9 for calling a global function with example usage: test_unbuild_with_loaded_tree() without return types