code: def test_input_validation_nobs(self):
      with pytest.raises(
          ValueError, match="same number of observations"
      ):
          ddm.distance_covariance_test(self.x[:2, :], self.y)
  
imports: import numpy
  from numpy.testing import assert_almost_equal
  import pytest
  from statsmodels.datasets import get_rdataset
  from statsmodels.datasets.tests.test_utils import IGNORED_EXCEPTIONS
  import statsmodels.stats.dist_dependence_measures
  from statsmodels.tools.sm_exceptions import HypothesisTestWarning
label_desc: Use image node_id 2 for calling the TestDistDependenceMeasures obj's underlying member method code with example usage: obj.test_input_validation_nobs() without return types