code: def test_emcee_float(self):
      # test that it works if the residuals returns a float, not a vector
      if not HAS_EMCEE:
          return True
  
      def resid(pars, x, data=None):
          return -0.5 * np.sum(self.residual(pars, x, data=data) ** 2)
  
      # just return chi2
      def resid2(pars, x, data=None):
          return np.sum(self.residual(pars, x, data=data) ** 2)
  
      self.mini.userfcn = resid
      np.random.seed(123456)
      out = self.mini.emcee(nwalkers=100, steps=200, burn=50, thin=10)
      check_paras(out.params, self.p_true, sig=3)
  
      self.mini.userfcn = resid2
      np.random.seed(123456)
      out = self.mini.emcee(
          nwalkers=100,
          steps=200,
          burn=50,
          thin=10,
          float_behavior="chi2",
      )
      check_paras(out.params, self.p_true, sig=3)
  
imports: import sys
  import unittest
  import numpy
  from numpy import pi
  from numpy.testing import assert_allclose, assert_almost_equal, assert_equal
  import pytest
  from scipy.optimize import rosen_der
  from uncertainties import ufloat
  from lmfit import Minimizer, Parameters, minimize
  from lmfit.lineshapes import gaussian
  from lmfit.minimizer import HAS_EMCEE, SCALAR_METHODS, MinimizerResult, coerce_float64
  from lmfit.models import SineModel
label_desc: Use image node_id 17 for calling the CommonMinimizerTest obj's underlying member method code with example usage: obj.test_emcee_float() and returns: True, unknown, np