public async Task<BoxRetentionPolicy> GetRetentionPolicyAsync(string id, List<string> fields = null) { id.ThrowIfNullOrWhiteSpace("id"); BoxRequest request = new BoxRequest(_config.RetentionPoliciesEndpointUri, id) .Param(ParamFields, fields); IBoxResponse<BoxRetentionPolicy> response = await ToResponseAsync<BoxRetentionPolicy>(request).ConfigureAwait(false); return response.ResponseObject; }