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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 _load_data(self, band):
 """From the WISE All-Sky Explanatory Supplement, IV.4.h.i.1, and Jarrett+ 2011. These are relative response per erg and so can be integrated directly against F_nu spectra. Wavelengths are in micron, uncertainties are in parts per thousand. """

        # `band` should be 1, 2, 3, or 4.
        df = bandpass_data_frame('filter_wise_' + str(band) + '.dat', 'wlen resp uncert')
        df.wlen *= 1e4 # micron to Angstrom
        df.uncert *= df.resp / 1000. # parts per thou. to absolute values.
        lo, hi = self._filter_subsets[band]
        df = df[lo:hi] # clip zero parts of response.
        return df