code: def test_dim(self, expected):
      self.assertEqual(self.space.dim, expected)
  
imports: import pytest
  import geomstats.backend
  from geomstats.test.random import RandomDataGenerator
  from geomstats.test.test_case import TestCase
  from geomstats.test.vectorization import generate_vectorization_data
label_desc: Use image node_id 2 for calling the _ManifoldTestCaseMixins obj's underlying member method code with example usage: obj.test_dim(expected) without return types