code: def test_op_table():
      from speechbrain.utils.edit_distance import op_table, EDIT_SYMBOLS
  
      assert len(op_table([1, 2, 3], [1, 2, 4])) == 4
      assert len(op_table([1, 2, 3], [1, 2, 4])[0]) == 4
      assert len(op_table([1, 2, 3], [])) == 4
      assert len(op_table([1, 2, 3], [])[0]) == 1
      assert op_table([1, 2, 3], [1, 2, 4])[3][3] == EDIT_SYMBOLS["sub"]
      assert op_table([1, 2, 3], [1, 2, 4])[2][2] == EDIT_SYMBOLS["eq"]
      assert op_table([1, 2, 3], [1, 2, 4])[0][0] == EDIT_SYMBOLS["eq"]
  
label_desc: Use image node_id 2 for calling a global function with example usage: test_op_table() without return types