verify if value is a list for multi variables

tiramisu/value.py

@@ -235,6 +235,8 @@ class Values:
                        value: Any,
                        force_allow_empty_list: bool,
                        ) -> bool:
+        if not isinstance(value, list):
+            return False
         return (not force_allow_empty_list and value == []) or None in value or '' in value
 
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