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