code: def test_invalid_y_grid():
      # check ygrid deprecation
      warnings.simplefilter("always")
      with warnings.catch_warnings(record=True) as w:
          etest_poisson_2indep(1, 1, 1, 1, ygrid=[1])
      assert len(w) == 1
      assert issubclass(w[0].category, FutureWarning)
      assert "ygrid" in str(w[0].message)
  
      # check y_grid validity
      with pytest.raises(ValueError) as e:
          etest_poisson_2indep(1, 1, 1, 1, y_grid=1)
      assert "y_grid" in str(e.value)
  
imports: import pytest
  import warnings
  import numpy
  from numpy import arange
  from numpy.testing import assert_allclose, assert_equal
  from scipy import stats
  import statsmodels.stats.rates
  from statsmodels.stats.rates import confint_poisson, tolerance_int_poisson, confint_quantile_poisson, etest_poisson_2indep, confint_poisson_2indep, nonequivalence_poisson_2indep, power_poisson_ratio_2indep, power_equivalence_poisson_2indep, power_poisson_diff_2indep, power_equivalence_neginb_2indep, power_negbin_ratio_2indep, method_names_poisson_1samp, method_names_poisson_2indep
label_desc: Use image node_id 14 for calling a global function with example usage: test_invalid_y_grid() without return types