How to use the webauthn.webauthn.WebAuthnCredential function in webauthn

# not trustworthy per step 16 above, the Relying Party SHOULD fail
            # the registration ceremony.
            #
            #     NOTE: However, if permitted by policy, the Relying Party MAY
            #           register the credential ID and credential public key but
            #           treat the credential as one with self attestation (see
            #           6.3.3 Attestation Types). If doing so, the Relying Party
            #           is asserting there is no cryptographic proof that the
            #           public key credential has been generated by a particular
            #           authenticator model. See [FIDOSecRef] and [UAFProtocol]
            #           for a more detailed discussion.

            sc = auth_data[33:37]
            sign_count = struct.unpack('!I', sc)[0]

            credential = WebAuthnCredential(
                self.rp_id, self.origin, _webauthn_b64_encode(cred_id),
                _webauthn_b64_encode(credential_public_key), sign_count)

            return credential

        except Exception as e:
            raise RegistrationRejectedException(
                'Registration rejected. Error: {}.'.format(e))