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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 _compute_std(self, C, mag, stddevs, idx):
 """ Compute total standard deviation, as explained in table 2, page 67. """

        if mag > 8.0:
            mag = 8.0

        for stddev in stddevs:
            stddev[idx] += C['C4'] + C['C5'] * mag