code: def test_single_document(self):
      with pytest.raises(
          TypeError,
          match="DocumentLanguageClassifier expects a list of Document as input.",
      ):
          classifier = DocumentLanguageClassifier()
          classifier.run(
              documents=Document(content="This is an english sentence.")
          )
  
file_path: haystack/test/components/classifiers/test_document_language_classifier.py
imports: import logging
  import pytest
  from haystack import Document
  from haystack.components.classifiers import DocumentLanguageClassifier
label_desc: Use image node_id 3 for calling the TestDocumentLanguageClassifier obj's underlying member method code with example usage: obj.test_single_document() without return types