code: def test_group_var_generic_1d(self):
      prng = np.random.default_rng(2)
  
      out = (np.nan * np.ones((5, 1))).astype(self.dtype)
      counts = np.zeros(5, dtype="int64")
      values = 10 * prng.random((15, 1)).astype(self.dtype)
      labels = np.tile(np.arange(5), (3,)).astype("intp")
  
      expected_out = (
          np.squeeze(values)
          .reshape((5, 3), order="F")
          .std(axis=1, ddof=1)
          ** 2
      )[:, np.newaxis]
      expected_counts = counts + 3
  
      self.algo(out, counts, values, labels)
      assert np.allclose(out, expected_out, self.rtol)
      tm.assert_numpy_array_equal(counts, expected_counts)
  
imports: import numpy
  import pytest
  from pandas._libs import groupby
  from pandas._libs.groupby import group_cumprod, group_cumsum, group_mean, group_sum, group_var
  from pandas.core.dtypes.common import ensure_platform_int
  from pandas import isna
  import pandas._testing
label_desc: Use image node_id 1 for calling the GroupVarTestMixin obj's underlying member method code with example usage: obj.test_group_var_generic_1d() without return types