code: def testGetSourceWriter(self):
      x = event_multiplexer.EventMultiplexer(
          {"run1": "path1", "run2": "path2"}
      )
      self.assertEqual(x.GetSourceWriter("run1"), "path1_writer")
      self.assertEqual(x.GetSourceWriter("run2"), "path2_writer")
  
imports: import os
  import os.path
  import shutil
  import tensorflow
  from tensorboard.backend.event_processing import event_accumulator
  from tensorboard.backend.event_processing import event_multiplexer
label_desc: Use image node_id 6 for calling the EventMultiplexerTest obj's underlying member method code with example usage: obj.testGetSourceWriter() without return types