code: def test_ndim(self):
      assert self.m.ndim == 2
  
imports: import pickle
  import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupy.cuda import driver
  from cupy.cuda import runtime
  from cupyx.scipy import sparse
label_desc: Use image node_id 6 for calling the TestDiaMatrix obj's underlying member method code with example usage: obj.test_ndim() without return types