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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 from_series(cls, series):
 """Convert a pandas.Series into an xarray.DataArray. If the series's index is a MultiIndex, it will be expanded into a tensor product of one-dimensional coordinates (filling in missing values with NaN). Thus this operation should be the inverse of the `to_series` method. """

        # TODO: add a 'name' parameter
        name = series.name
        df = pd.DataFrame({name: series})
        ds = Dataset.from_dataframe(df)
        return ds[name]