code: def test_empty_doc(vocab):
      doc = Doc(vocab)
      assert len(doc) == 0
  
file_path: spaCy/spacy/tests/doc/test_creation.py
imports: import pytest
  from spacy import util
  from spacy.tokens import Doc
  from spacy.vocab import Vocab
label_desc: Use image node_id 2 for calling a global function with example usage: test_empty_doc(vocab) without return types