Update src/ghga_transpiler/metasheet_parser.py

Co-authored-by: Christoph Zwerschke <[email protected]>

src/ghga_transpiler/metasheet_parser.py

@@ -95,7 +95,9 @@ def reshape_settings_meta(settings_meta: list, name_column: str) -> dict[str, di
             raise MetaColumnNotFound(
                 f"{name_column} column not found in settings meta sheet"
             ) from err
-        worksheet_settings.setdefault(sheet_name, item)
+        if sheet_name in worksheet_settings:
+            raise MetaColumnNotUnique(f"Duplicate sheet name {sheet_name} in settings meta column {name_column}")
+        worksheet_settings[sheet_name] = item
     return worksheet_settings