diff --git a/src/zcl_excel_legacy_palette.clas.abap b/src/zcl_excel_legacy_palette.clas.abap
index c3d19eb..14e6166 100644
--- a/src/zcl_excel_legacy_palette.clas.abap
+++ b/src/zcl_excel_legacy_palette.clas.abap
@@ -24,7 +24,9 @@ public section.
   methods SET_COLOR
     importing
       !IP_INDEX type I
-      !IP_COLOR type ZEXCEL_STYLE_COLOR_ARGB .
+      !IP_COLOR type ZEXCEL_STYLE_COLOR_ARGB 
+    raising
+      ZCX_EXCEL .
 protected section.
 *"* protected components of class ZCL_EXCEL_LEGACY_PALETTE
 *"* do not include other source files here!!!