code: def test_remove_self_loops():
      edge_indices = np.array([[1, 2, 3], [1, 2, 4]])
      edge_indices = remove_self_loops(edge_indices)
      assert edge_indices.shape[0] == 2
      assert edge_indices.shape[1] == 1
  
      edge_indices = np.ones((2, 3))
      edge_indices = remove_self_loops(edge_indices)
      assert edge_indices.shape[0] == 2
      assert edge_indices.shape[1] == 0
  
imports: import numpy
  from deepchem.utils.fake_data_generator import FakeGraphGenerator, generate_edge_index, remove_self_loops
label_desc: Use image node_id 3 for calling a global function with example usage: test_remove_self_loops() without return types