code: def test_linker_has_types(self):
      # Just checking that the type tree is accessible from the linker
      assert len(self.linker.kb.semantic_type_tree.flat_nodes) == 6
  
file_path: scispacy/tests/test_linking.py
imports: import unittest
  import tempfile
  import spacy
  from scispacy.candidate_generation import CandidateGenerator, create_tfidf_ann_index
  from scispacy.linking import EntityLinker
  from scispacy.umls_utils import UmlsKnowledgeBase
  from scispacy.abbreviation import AbbreviationDetector
label_desc: Use image node_id 4 for calling the TestLinker obj's underlying member method code with example usage: obj.test_linker_has_types() without return types