You can use double quote when defining a concept name to protect keyword

tests/parsers/test_DefaultParser.py

@@ -311,6 +311,18 @@ def concept add one to a as
 
         assert not parser.has_error
 
+    @pytest.mark.parametrize("text", [
+        'def concept "def concept x"',
+        'def concept "def concept x" as x',
+    ])
+    def test_i_can_use_double_quotes_to_protect_keywords(self, text):
+        sheerka, context, parser = self.init_parser()
+        res = parser.parse(context, ParserInput(text))
+        concept_defined = res.value.value
+
+        assert res.status
+        assert concept_defined.name.tokens == list(Tokenizer("def concept x", yield_eof=False))
+
     @pytest.mark.parametrize("text", [
         "def concept name from bnf as here is my body",
         "def concept name from def as here is my body",
@@ -380,20 +392,6 @@ def concept add one to a as
         assert context.sheerka.isinstance(res.value, BuiltinConcepts.NOT_FOR_ME)
         assert isinstance(res.value.body[0], CannotHandleErrorNode)
 
-    # def test_i_can_parse_is_a(self):
-    #     text = "the name of my 'concept' isa the name of the set"
-    #     sheerka, context, parser = self.init_parser()
-    #     res = parser.parse(context, ParserInput(text))
-    #     expected = IsaConceptNode([],
-    #                               concept=NameNode(list(Tokenizer("the name of my 'concept'"))),
-    #                               set=NameNode(list(Tokenizer("the name of the set"))))
-    #
-    #     assert res.status
-    #     assert res.who == parser.name
-    #     assert res.value.source == text
-    #     assert isinstance(res.value, ParserResultConcept)
-    #     assert res.value.value == expected
-
     @pytest.mark.parametrize("text", [
         "def",
         "def concept_name"