code: def test_2m_1cf(self, mf_2m_1cf: MetricFrame):
      assert isinstance(mf_2m_1cf.by_group_ci, list)
      assert len(mf_2m_1cf.by_group_ci) == len(QUANTILES)
      assert mf_2m_1cf.ci_quantiles == QUANTILES
  
      for m in ["mse", "group_frac"]:
          for cf in np.unique(g_2):
              for g in np.unique(g_1):
                  # Check median close to nominal
                  assert mf_2m_1cf.by_group_ci[1][m][cf][
                      g
                  ] == pytest.approx(
                      mf_2m_1cf.by_group[m][cf][g], abs=ABS_TOL
                  )
  
imports: import numpy
  import pytest
  import sklearn.metrics
  from fairlearn.metrics import MetricFrame, count
  from .data_for_test import g_1, g_2, y_p, y_t
label_desc: Use image node_id 4 for calling the TestByGroupQuantiles obj's underlying member method code with example usage: obj.test_2m_1cf(mf_2m_1cf) without return types