code: def public_pairs_for_script(self, tx, tx_in_idx, generator):
          
          public_pairs = []
          for sec in self.extract_secs(tx, tx_in_idx):
              try:
                  public_pairs.append(sec_to_public_pair(sec, generator))
              except EncodingError:
                  pass
          return public_pairs
docs: For a given script, iterate over and pull out public pairs encoded as sec values.