code: def nloglikeobs(self, params):
      alph = params[-1]
      beta = params[:-1]
      ll = _ll_nb2(self.endog, self.exog, beta, alph)
      return -ll
  
file_path: statsmodels/examples/python/generic_mle.py
imports: import numpy
  from scipy import stats
  import statsmodels.api
  from statsmodels.base.model import GenericLikelihoodModel
  import numpy
  from scipy.stats import nbinom
  from statsmodels.base.model import GenericLikelihoodModel
  import statsmodels.api
label_desc: Use image node_id 2 for calling the NBin obj's underlying member method code with example usage: obj.nloglikeobs(params) and returns: unknown