class_docstr: Results class for QIF Regression
docstr: An AIC-like statistic for models fit using QIF.
docstr_tok: ["An","AIC-like","statistic","for","models","fit","using","QIF","."]
code: def aic(self):
      """
      An AIC-like statistic for models fit using QIF.
      """
      if isinstance(self.model.cov_struct, QIFIndependence):
          msg = "AIC not available with QIFIndependence covariance"
          raise ValueError(msg)
      df = self.model.exog.shape[1]
      return self.qif + 2 * df
  
imports: import numpy
  from collections import defaultdict
  import statsmodels.base.model
  from statsmodels.genmod import families
  from statsmodels.genmod.generalized_linear_model import GLM
  from statsmodels.genmod.families import links
  from statsmodels.genmod.families import varfuncs
  import statsmodels.regression.linear_model
  import statsmodels.base.wrapper
  from statsmodels.tools.decorators import cache_readonly
label_desc: Use image node_id 2 for calling the QIFResults obj's underlying member method code with example usage: obj.aic() and returns: unknown