class_docstr: Test that a keyword-based log-probability function instead of
  a positional.
class_docstr_tok: ["Test","that","a","keyword-based","log-probability","function","instead","of","a","positional","."]
code: def lnpdf_mixture_grouped(self, pars) -> np.float64:
      mean1, mean2 = pars["means"]
      var1, var2 = pars["vars"]
      const = pars["constant"]
      if var1 <= 0 or var2 <= 0:
          return -np.inf
      return (
          -0.5
          * (
              (mean1 - self.x) ** 2 / var1
              + np.log(2 * np.pi * var1)
              + (mean2 - self.x - 3) ** 2 / var2
              + np.log(2 * np.pi * var2)
          ).sum()
          + const
      )
  
file_path: emcee/src/emcee/tests/unit/test_ensemble.py
imports: import string
  from unittest import TestCase
  import numpy
  import pytest
  from emcee.ensemble import EnsembleSampler, ndarray_to_list_of_dicts
label_desc: Use image node_id 3 for calling the TestNamedParameters obj's underlying member method code with example usage: obj.lnpdf_mixture_grouped(pars) and returns: unknown, unknown