Implemented ConceptManager with concept creation, modification and deletion

src/evaluators/AddConceptInSetEvaluator.py

@@ -56,10 +56,6 @@ class AddConceptInSetEvaluator(OneReturnValueEvaluator):
                 parents=[return_value])
         concept = res.value
 
-        if sheerka.has_id(concept.id) and id(concept) == id(sheerka.get_by_id(concept.id)):
-            # hack because it is not possible to use sheerka.modify_concept() on a cache instance
-            concept = sheerka.new((concept.name, concept.id))
-
         res = _resolve(isa_node.set)
         if not res.status:
             return sheerka.ret(

src/evaluators/PythonEvaluator.py

@@ -158,7 +158,11 @@ class PythonEvaluator(OneReturnValueEvaluator):
 
         context.log(f"{evaluated=}", self.name)
         debugger.debug_var("ret", evaluated)
-        return sheerka.ret(self.name, True, evaluated, parents=[return_value])
+
+        if sheerka.isinstance(evaluated, BuiltinConcepts.RETURN_VALUE):
+            return sheerka.ret(self.name, evaluated.status, evaluated.body, parents=[return_value, evaluated])
+        else:
+            return sheerka.ret(self.name, True, evaluated, parents=[return_value])
 
     def get_globals(self, context, node, expression_only):
         """