def _validate_token(self, token, scopes_required=None):
        """The actual implementation of validate_token."""
        if scopes_required is None:
            scopes_required = []
        scopes_required = set(scopes_required)

        token_info = None
        valid_token = False
        has_required_scopes = False
        if token:
            try:
                token_info = self._get_token_info(token)
            except Exception as ex:
                token_info = {'active': False}
                logger.error('ERROR: Unable to get token info')
                logger.error(str(ex))

            valid_token = token_info.get('active', False)

            if 'aud' in token_info and \
                    current_app.config['OIDC_RESOURCE_CHECK_AUD']:
                valid_audience = False
                aud = token_info['aud']
                clid = self.client_secrets['client_id']
                if isinstance(aud, list):
                    valid_audience = clid in aud
                else:
                    valid_audience = clid == aud

                if not valid_audience:
                    logger.error('Refused token because of invalid '
                                 'audience')
                    valid_token = False

            if valid_token:
                token_scopes = token_info.get('scope', '').split(' ')
            else:
                token_scopes = []
            has_required_scopes = scopes_required.issubset(
                set(token_scopes))

            if not has_required_scopes:
                logger.debug('Token missed required scopes')

        if (valid_token and has_required_scopes):
            g.oidc_token_info = token_info
            return True

        if not valid_token:
            return 'Token required but invalid'
        elif not has_required_scopes:
            return 'Token does not have required scopes'
        else:
            return 'Something went wrong checking your token'
The actual implementation of validate_token.