code: def test_sents(self):
      sents = conll2007.sents("esp.train")[0]
      self.assertEqual(
          sents[:6],
          ["El", "aumento", "del", "índice", "de", "desempleo"],
      )
  
imports: import unittest
  import pytest
  from nltk.corpus import cess_cat, cess_esp, conll2007, floresta, indian, ptb, sinica_treebank, udhr
  from nltk.tree import Tree
label_desc: Use image node_id 1 for calling the TestCoNLL2007 obj's underlying member method code with example usage: obj.test_sents() without return types