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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 fit_lsq(self, df):
 """ Parameterize generic SAR curve from empirical data set Parameters df : DataFrame Result data frame from empirical SAR analysis Notes ----- Simply returns S0 and N0 from empirical SAR output, which are two fixed parameters of METE SAR and EAR. This simply returns n_spp and n_individs from the 1,1 division in the dataframe. An error will be thrown if this division is not present The ``fit_lsq`` is retained for consistency with other curves. """

        tdf = df.set_index('div')
        return tdf.ix['1,1']['n_spp'], tdf.ix['1,1']['n_individs']