code: def runTest(self):
      multi_document_assembler = (
          MultiDocumentAssembler()
          .setInputCols("input1", "input2")
          .setOutputCols("output1", "output2")
      )
  
      tokenizer = (
          Tokenizer().setInputCols("output2").setOutputCol("token")
      )
  
      pipeline = Pipeline().setStages(
          [multi_document_assembler, tokenizer]
      )
      result_df = pipeline.fit(self.twoInputDataSet).transform(
          self.twoInputDataSet
      )
  
      output1 = result_df.select("output1.result").collect()[0]
      output2 = result_df.select("output2.result").collect()[0]
      tokens = result_df.select("token.result").collect()[0]
  
      self.assertGreater(len(output1), 0)
      self.assertGreater(len(output2), 0)
      self.assertGreater(len(tokens), 0)
  
imports: import unittest
  import pytest
  from sparknlp.base import *
  from sparknlp.annotator import *
  from test.util import SparkSessionForTest
label_desc: Use image node_id 2 for calling the MultiDocumentAssemblerTest obj's underlying member method code with example usage: obj.runTest() without return types