code: def get_certificates_der_v3(self):
          
  
          if self._v3_signing_data == None:
              self.parse_v3_signing_block()
  
          certs = []
          for signed_data in [signer.signed_data for signer in self._v3_signing_data]:
              for cert in signed_data.certificates:
                  certs.append(cert)
  
          return certs
docs: Return a list of DER coded X.509 certificates from the v3 signature block