code: def test_report_fixed_parameter(fitresult):
      """Verify that a fixed parameter is shown correctly."""
      fitresult.params["center"].vary = False
      report_split = fitresult.fit_report().split("\n")
      indx = [
          i for i, val in enumerate(report_split) if "center" in val
      ][0]
      assert "(fixed)" in report_split[indx]
  
imports: import numpy
  import pytest
  import lmfit
  from lmfit import Minimizer, Parameters, ci_report, conf_interval, fit_report, report_ci, report_fit
  from lmfit.lineshapes import gaussian
  from lmfit.models import GaussianModel
  from lmfit.printfuncs import alphanumeric_sort, correl_table, fitreport_html_table, getfloat_attr, gformat
label_desc: Use image node_id 18 for calling a global function with example usage: test_report_fixed_parameter(fitresult) without return types