code: def test_n(self, n, doc_en):
      result = list(extract.ngrams(doc_en, n))
      assert all(isinstance(span, Span) for span in result)
      assert all(len(span) == n for span in result)
  
imports: import collections
  import pytest
  from spacy.tokens import Span, Token
  from textacy import extract
  from textacy.extract import basics
label_desc: Use image node_id 1 for calling the TestNGrams obj's underlying member method code with example usage: obj.test_n(n, doc_en) without return types