Added ModifyConcept function, and fixed 'isa' not working

tests/BaseTest.py

@@ -36,23 +36,26 @@ class BaseTest:
     def init_concepts(self, *concepts, **kwargs):
         sheerka = self.get_sheerka(**kwargs)
         context = self.get_context(sheerka)
+        create_new = kwargs.get("create_new", False)
 
         result = []
         for c in concepts:
             if isinstance(c, str):
                 c = Concept(c)
-            c.init_key()
-            sheerka.set_id_if_needed(c, False)
 
-            # manage concepts with bnf definitions
             if c.metadata.definition:
                 bnf_parser = BnfParser()
                 res = bnf_parser.parse(context, c.metadata.definition)
                 if res.status:
                     c.bnf = res.value.value
                 sheerka.create_new_concept(context, c)
+            elif create_new:
+                sheerka.create_new_concept(context, c)
+            else:
+                c.init_key()
+                sheerka.set_id_if_needed(c, False)
+                sheerka.add_in_cache(c)
 
-            sheerka.add_in_cache(c)
             result.append(c)
 
         return sheerka, context, *result