code: def _add_series_or_dataframe_operations(cls):
          
  
          from pandas.core import window as rwindow
  
          @Appender(rwindow.rolling.__doc__)
          def rolling(self, window, min_periods=None, center=False,
                      win_type=None, on=None, axis=0, closed=None):
              axis = self._get_axis_number(axis)
              return rwindow.rolling(self, window=window,
                                     min_periods=min_periods,
                                     center=center, win_type=win_type,
                                     on=on, axis=axis, closed=closed)
  
          cls.rolling = rolling
  
          @Appender(rwindow.expanding.__doc__)
          def expanding(self, min_periods=1, center=False, axis=0):
              axis = self._get_axis_number(axis)
              return rwindow.expanding(self, min_periods=min_periods,
                                       center=center, axis=axis)
  
          cls.expanding = expanding
  
          @Appender(rwindow.ewm.__doc__)
          def ewm(self, com=None, span=None, halflife=None, alpha=None,
                  min_periods=0, adjust=True, ignore_na=False,
                  axis=0):
              axis = self._get_axis_number(axis)
              return rwindow.ewm(self, com=com, span=span, halflife=halflife,
                                 alpha=alpha, min_periods=min_periods,
                                 adjust=adjust, ignore_na=ignore_na, axis=axis)
  
          cls.ewm = ewm
docs: Add the series or dataframe only operations to the cls; evaluate
          the doc strings again.