def request(self, method, url, params=None, headers=None, access_token=None, **aio_kwargs):
        """Request OAuth2 resource."""
        url = self._get_url(url)
        params = params or {}

        access_token = access_token or self.access_token
        if access_token:
            if isinstance(params, list):
                if self.access_token_key not in dict(params):
                    params.append((self.access_token_key, access_token))

            else:
                params[self.access_token_key] = access_token

        headers = headers or {
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
        }
        return self._request(method, url, params=params, headers=headers, **aio_kwargs)
Request OAuth2 resource.