code: def assert_training_example(self, predicted_training_example):
      relations = predicted_training_example.get_relations("relation")
      assert len(relations) == 1
      assert relations[0].tag == "founded_by"
  
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 5 for calling the TestRelationExtractor obj's underlying member method code with example usage: obj.assert_training_example(predicted_training_example) without return types