code: def test_add_text(model=classify.Bo1Model):
      ix = create_index()
      with ix.reader() as r:
          exp = classify.Expander(r, "content", model=model)
          exp.add_text(text)
          assert set([t[0] for t in exp.expanded_terms(3)]) == set(
              ["particles", "velocity", "field"]
          )
          exp = classify.Expander(r, "extra", model=model)
          exp.add_text(text)
          assert exp.expanded_terms(3) == []
  
file_path: whoosh/tests/test_classify.py
imports: from __future__ import with_statement
  from whoosh import analysis, classify, fields, formats, query, reading
  from whoosh.compat import u, text_type
  from whoosh.filedb.filestore import RamStorage
  from whoosh.util.testing import TempIndex
label_desc: Use image node_id 2 for calling a global function with example usage: test_add_text(model) without return types