class_docstr: Results class for OrderedModel
  
  This class inherits from GenericLikelihoodModelResults and not all
  inherited methods might be appropriate in this case.
docstr: Value of the loglikelihood of model without explanatory variables
code: def llnull(self):
      """
      Value of the loglikelihood of model without explanatory variables
      """
      params_null = self.model.start_params
      return self.model.loglike(params_null)
  
imports: import warnings
  from statsmodels.compat.pandas import Appender
  import numpy
  import pandas
  from pandas.api.types import CategoricalDtype
  from scipy import stats
  from statsmodels.base.model import Model, LikelihoodModel, GenericLikelihoodModel, GenericLikelihoodModelResults
  import statsmodels.base.wrapper
  import statsmodels.regression.linear_model
  from statsmodels.tools.decorators import cache_readonly
label_desc: Use image node_id 2 for calling the OrderedResults obj's underlying member method code with example usage: obj.llnull() and returns: self