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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 observed(self, band, corrected=True):
 """Return observed values in the given band Parameters band : str desired bandpass: should be one of ['u', 'g', 'r', 'i', 'z'] corrected : bool (optional) If true, correct for extinction Returns ------- t, mag, dmag : ndarrays The times, magnitudes, and magnitude errors for the specified band. """

        if band not in 'ugriz':
            raise ValueError("band='{0}' not recognized".format(band))
        i = 'ugriz'.find(band)
        t, y, dy = self.lcdata.get_lightcurve(self.lcid, return_1d=False)

        if corrected:
            ext = self.obsmeta['rExt'] * self.ext_correction[band]
        else:
            ext = 0

        return t[:, i], y[:, i] - ext, dy[:, i]