class_docstr: Class responsible for handling input data and extracting metadata into the
  appropriate form
class_docstr_tok: ["Class","responsible","for","handling","input","data","and","extracting","metadata","into","the","appropriate","form"]
code: def ynames(self):
      endog = self.orig_endog
      ynames = self._get_names(endog)
      if not ynames:
          ynames = _make_endog_names(self.endog)
  
      if len(ynames) == 1:
          return ynames[0]
      else:
          return list(ynames)
  
imports: from __future__ import annotations
  from statsmodels.compat.python import lmap
  from functools import reduce
  import numpy
  from pandas import DataFrame, Series, isnull, MultiIndex
  import statsmodels.tools.data
  from statsmodels.tools.decorators import cache_readonly, cache_writable
  from statsmodels.tools.sm_exceptions import MissingDataError
label_desc: Use image node_id 9 for calling the ModelData obj's underlying member method code with example usage: obj.ynames() and returns: ynames, list