diff --git a/slic/utils/argfwd.py b/slic/utils/argfwd.py
index cdd7065c2..b53ee697c 100644
--- a/slic/utils/argfwd.py
+++ b/slic/utils/argfwd.py
@@ -29,7 +29,8 @@ def forwards_to(func_inner, nfilled=0, appended_kwargs=None):
 
 
 def get_args(func):
-    spec = inspect.getfullargspec(func) #TODO replace by inspect.signature?
+    spec = inspect.signature(func)
+    #spec = inspect.getfullargspec(func) #TODO replace by inspect.signature?
     all_args = spec.args
 
     defaults = spec.defaults or []