code: def test_count_categories(self):
      self.grouping.count_categories(level=0)
      np.testing.assert_equal(
          self.grouping.counts, self.expected_counts
      )
  
imports: from statsmodels.compat.pandas import assert_frame_equal, assert_series_equal
  import numpy
  from numpy.testing import assert_equal
  import pandas
  import pytest
  from scipy import sparse
  from statsmodels.tools.grouputils import dummy_sparse, Grouping, Group, combine_indices, group_sums
  from statsmodels.datasets import grunfeld, anes96
label_desc: Use image node_id 2 for calling the CheckGrouping obj's underlying member method code with example usage: obj.test_count_categories() without return types