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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 get_ppis(self, ppi_df):
 """Generate Complex Statements from the HPRD PPI data. Parameters ppi_df : pandas.DataFrame DataFrame loaded from the BINARY_PROTEIN_PROTEIN_INTERACTIONS.txt file. """

        logger.info('Processing PPIs...')
        for ix, row in ppi_df.iterrows():
            agA = self._make_agent(row['HPRD_ID_A'])
            agB = self._make_agent(row['HPRD_ID_B'])
            # If don't get valid agents for both, skip this PPI
            if agA is None or agB is None:
                continue
            isoform_id = '%s_1' % row['HPRD_ID_A']
            ev_list = self._get_evidence(
                    row['HPRD_ID_A'], isoform_id, row['PMIDS'],
                    row['EVIDENCE'], 'interactions')
            stmt = Complex([agA, agB], evidence=ev_list)
            self.statements.append(stmt)