Fixed some bugs

tests/non_reg/test_sheerka_non_reg.py

@@ -963,6 +963,19 @@ as:
         assert res[0].status
         assert res[0].body == 21
 
+    def test_i_can_use_last_created_concept_to_define_set(self):
+        init = [
+            "def concept number",
+            "def concept one",
+        ]
+
+        sheerka = self.init_scenario(init)
+
+        res = sheerka.evaluate_user_input("last_created_concept() isa number")
+
+        assert res[0].status
+        assert sheerka.isa(sheerka.new("one"), sheerka.new("number"))
+
 
 class TestSheerkaNonRegFile(TestUsingFileBasedSheerka):
     def test_i_can_def_several_concepts(self):