code: def example_sentence(self):
      sentence = Sentence(
          ["Microsoft", "was", "found", "by", "Bill", "Gates"]
      )
      sentence[:1].add_label(typename="ner", value="ORG", score=1.0)
      sentence[4:].add_label(typename="ner", value="PER", score=1.0)
      return sentence
  
file_path: flair/tests/models/test_relation_extractor.py
imports: import pytest
  from flair.data import Sentence
  from flair.datasets import ColumnCorpus
  from flair.embeddings import TransformerWordEmbeddings
  from flair.models import RelationExtractor
  from tests.model_test_utils import BaseModelTest
label_desc: Use image node_id 2 for calling the TestRelationExtractor obj's underlying member method code with example usage: obj.example_sentence() and returns: sentence