code: def testDummyScreensAddedToNewMemory(self):
      memory = self.create_default_memory()
      index = self.add_blank(memory)
      for i in range(index):
          self.assertEqual(memory.sum_tree.get(i), 0.0)
  
file_path: ReAgent/reagent/test/replay_memory/prioritized_replay_buffer_test.py
imports: import unittest
  import numpy
  from reagent.replay_memory import prioritized_replay_buffer
label_desc: Use image node_id 4 for calling the PrioritizedReplayBufferTest obj's underlying member method code with example usage: obj.testDummyScreensAddedToNewMemory() without return types