code: def test_confidence_pnames(data, pars):
      """Test if pnames works as expected."""
      minimizer = lmfit.Minimizer(residual, pars, fcn_args=(data))
      out = minimizer.leastsq()
  
      assert_allclose(out.params["a"], 0.1, rtol=0.01)
      assert_allclose(out.params["b"], 2.0, rtol=0.01)
  
      ci = lmfit.conf_interval(minimizer, out, p_names=["a"])
      assert "a" in ci
      assert "b" not in ci
  
imports: import copy
  import numpy
  from numpy.testing import assert_allclose
  import pytest
  from scipy.stats import f
  import lmfit
label_desc: Use image node_id 7 for calling a global function with example usage: test_confidence_pnames(data, pars) without return types