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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 _drop_duplicate_ij(self):
 """ Drops duplicate entries from the network dataframe. """

        self.network['ij'] = list(map(lambda x: tuple(sorted(x)), list(
            zip(*[self.network['i'].values, self.network['j'].values]))))
        self.network.drop_duplicates(['ij', 't'], inplace=True)
        self.network.reset_index(inplace=True, drop=True)
        self.network.drop('ij', inplace=True, axis=1)