Refactord Concept class to regroup all builtins properties into a ConceptMetadata class

core/builtin_helpers.py

@@ -49,7 +49,7 @@ def expect_one(context, return_values):
         return sheerka.ret(
             context.who,
             False,
-            sheerka.new(BuiltinConcepts.IS_EMPTY, obj=return_values),
+            sheerka.new(BuiltinConcepts.IS_EMPTY, body=return_values),
             parents=return_values)
 
     successful_results = [item for item in return_values if item.status]
@@ -77,14 +77,14 @@ def expect_one(context, return_values):
             return sheerka.ret(
                 context.who,
                 False,
-                sheerka.new(BuiltinConcepts.TOO_MANY_SUCCESS, obj=successful_results),
+                sheerka.new(BuiltinConcepts.TOO_MANY_SUCCESS, body=successful_results),
                 parents=return_values)
 
     # only errors, i cannot help you
     return sheerka.ret(
         context.who,
         False,
-        sheerka.new(BuiltinConcepts.TOO_MANY_ERRORS, obj=return_values),
+        sheerka.new(BuiltinConcepts.TOO_MANY_ERRORS, body=return_values),
         parents=return_values)