code: def test_empty(self):
      data = np.array([])
      self.query_points = np.array([])
      with self.assertRaises(AssertionError):
          episodic_memory.knn_query(
              data, self.query_points, num_neighbors=2
          )
  
file_path: rlax/rlax/_src/episodic_memory_test.py
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import chex
  import jax
  import numpy
  from rlax._src import episodic_memory
label_desc: Use image node_id 4 for calling the KNNQueryTest obj's underlying member method code with example usage: obj.test_empty() without return types