code: def _get_data(self, idx):
      window = self._window
      if idx >= window:
          loc = slice(idx - window, idx)
      else:
          loc = slice(idx)
      y = self._y[loc]
      wy = self._wy[loc]
      wx = self._wx[loc]
      weights = self._weights[loc]
      missing = self._is_nan[loc]
      not_missing = ~missing
      if np.any(missing):
          y = y[not_missing]
          wy = wy[not_missing]
          wx = wx[not_missing]
          weights = weights[not_missing]
      return y, wy, wx, weights, not_missing
  
imports: from statsmodels.compat.numpy import lstsq
  from statsmodels.compat.pandas import Appender, Substitution, cache_readonly, call_cached_func, get_cached_doc
  from collections import namedtuple
  import numpy
  from pandas import DataFrame, MultiIndex, Series
  from scipy import stats
  from statsmodels.base import model
  from statsmodels.base.model import LikelihoodModelResults, Model
  from statsmodels.regression.linear_model import RegressionModel, RegressionResults
  from statsmodels.tools.validation import array_like, int_like, string_like
label_desc: Use image node_id 4 for calling the RollingWLS obj's underlying member method code with example usage: obj._get_data(idx) and returns: y,  wy,  wx,  weights,  not_missing