code: def test_topn_float(doc_long_en):
      result = kt.sgrank(doc_long_en, topn=0.2)
      assert len(result) > 0
      with pytest.raises(ValueError):
          _ = kt.sgrank(doc_long_en, topn=2.0)
  
file_path: textacy/tests/extract/keyterms/test_sgrank.py
imports: import pytest
  import textacy
  from textacy.extract import keyterms
label_desc: Use image node_id 6 for calling a global function with example usage: test_topn_float(doc_long_en) without return types