code: def _getnames(self, yname=None, xname=None):
      """extract names from model or construct names"""
      if yname is None:
          if getattr(self.model, "endog_names", None) is not None:
              yname = self.model.endog_names
          else:
              yname = "y"
  
      if xname is None:
          if getattr(self.model, "exog_names", None) is not None:
              xname = self.model.exog_names
          else:
              xname = ["var_%d" % i for i in range(len(self.params))]
  
      return yname, xname
  
imports: from statsmodels.compat.python import lmap, lrange, lzip
  import copy
  from itertools import zip_longest
  import time
  import numpy
  from statsmodels.iolib.table import SimpleTable
  from statsmodels.iolib.tableformatting import fmt_2, fmt_2cols, fmt_params, gen_fmt
  from .summary2 import _model_types
label_desc: Use image node_id 4 for calling a global function with example usage: _getnames(yname, xname) and returns: yname,  xname