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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def construct(self, window_dim, stride=1, fill_value=dtypes.NA):
 """ Convert this rolling object to xr.DataArray, where the window dimension is stacked as a new dimension Parameters window_dim: str New name of the window dimension. stride: integer, optional Size of stride for the rolling window. fill_value: optional. Default dtypes.NA Filling value to match the dimension size. Returns ------- DataArray that is a view of the original array. The returned array is not writeable. Examples -------- <xarray.DataArray (a: 2, b: 4, window_dim: 3)> array([[[np.nan, np.nan, 0], [np.nan, 0, 1], [0, 1, 2], [1, 2, 3]], [[np.nan, np.nan, 4], [np.nan, 4, 5], [4, 5, 6], [5, 6, 7]]]) Dimensions without coordinates: a, b, window_dim <xarray.DataArray (a: 2, b: 4, window_dim: 3)> array([[[np.nan, 0, 1], [0, 1, 2], [1, 2, 3], [2, 3, np.nan]], [[np.nan, 4, 5], [4, 5, 6], [5, 6, 7], [6, 7, np.nan]]]) Dimensions without coordinates: a, b, window_dim """


        from .dataarray import DataArray

        window = self.obj.variable.rolling_window(self.dim, self.window,
                                                  window_dim, self.center,
                                                  fill_value=fill_value)
        result = DataArray(window, dims=self.obj.dims + (window_dim,),
                           coords=self.obj.coords)
        return result.isel(**{self.dim: slice(None, None, stride)})