code: def testSetNegativeValue(self):
      with self.assertRaises(
          ValueError,
          msg="Sum tree values should be nonnegative. Got -1",
      ):
          self._tree.set(node_index=0, value=-1)
  
imports: import random
  import unittest
  from reagent.replay_memory import sum_tree
label_desc: Use image node_id 3 for calling the SumTreeTest obj's underlying member method code with example usage: obj.testSetNegativeValue() without return types