Fixed error when desc() returns multiple results

src/core/builtin_concepts.py

@@ -106,6 +106,7 @@ class BuiltinConcepts:
     # formatting
     TO_LIST = "__TO_LIST"
     TO_DICT = "__TO_DICT"
+    TO_MULTI = "__TO_MULTI"  # used when there are multiple output to display
 
 
 AllBuiltinConcepts = [v for n, v in BuiltinConcepts.__dict__.items() if not n.startswith("__")]
@@ -178,6 +179,13 @@ BuiltinContainers = [
     BuiltinConcepts.EXPLANATION,
     BuiltinConcepts.TO_LIST,
     BuiltinConcepts.TO_DICT,
+    BuiltinConcepts.TO_MULTI,
+]
+
+BuiltinOutConcepts = [
+    BuiltinConcepts.TO_LIST,
+    BuiltinConcepts.TO_DICT,
+    BuiltinConcepts.TO_MULTI,
 ]
 
 """