code: def runTest(self):
      document_assembler = (
          DocumentAssembler()
          .setInputCol("text")
          .setOutputCol("document")
      )
  
      sentence_detector = (
          SentenceDetectorDLModel.pretrained()
          .setInputCols(["document"])
          .setOutputCol("sentence")
      )
  
      ld = LanguageDetectorDL.pretrained()
  
      pipeline = Pipeline(
          stages=[document_assembler, sentence_detector, ld]
      )
  
      # list all the languages
      print(ld.getLanguages())
  
      model = pipeline.fit(self.data)
      model.transform(self.data).show()
  
file_path: spark-nlp/python/test/annotator/ld_dl/language_detector_dl_test.py
imports: import os
  import unittest
  import pytest
  from sparknlp.annotator import *
  from sparknlp.base import *
  from test.util import SparkContextForTest
label_desc: Use image node_id 2 for calling the LanguageDetectorDLTestSpec obj's underlying member method code with example usage: obj.runTest() without return types