code: def test_compute_ring_normal(self):
      normal = compute_ring_normal(self.cycle4, range(4))
      self.assertTrue(
          np.allclose(
              np.abs(normal / np.linalg.norm(normal)), [0, 0, 1]
          )
      )
  
imports: import os
  import unittest
  import numpy
  from deepchem.utils.rdkit_utils import load_molecule
  from deepchem.utils.rdkit_utils import compute_ring_center
  from deepchem.utils.rdkit_utils import compute_ring_normal
  from deepchem.utils.noncovalent_utils import is_pi_parallel
  from deepchem.utils.noncovalent_utils import is_pi_t
  from deepchem.utils.noncovalent_utils import compute_pi_stack
  from deepchem.utils.noncovalent_utils import is_cation_pi
  from deepchem.utils.noncovalent_utils import compute_cation_pi
  from deepchem.utils.noncovalent_utils import compute_binding_pocket_cation_pi
label_desc: Use image node_id 3 for calling the TestPiInteractions obj's underlying member method code with example usage: obj.test_compute_ring_normal() without return types