docs: public ApiResponse<Void> postUiOpenwindowNewmailWithHttpInfo(String datasource, String token, UiNewMail uiNewMail)
              throws ApiException {
          com.squareup.okhttp.Call call = postUiOpenwindowNewmailValidateBeforeCall(datasource, token, uiNewMail, null);
          return apiClient.execute(call);
      }