fixed param handling

conftest.py

@@ -13,7 +13,7 @@ def emtest_session() -> EmTest:
 
 @pytest.fixture
 def emtest(request: pytest.FixtureRequest, emtest_session: EmTest) -> EmTest:
-    if request.param and request.param is bool:
+    if hasattr(request, "param") and isinstance(request.param, bool):
         emtest_session.multiplexer.inverted = request.param
     emtest_session.setup_method("empty")
     return emtest_session