diff --git a/pyerrors/input/sfcf.py b/pyerrors/input/sfcf.py
index 89cda7e1..383bac56 100644
--- a/pyerrors/input/sfcf.py
+++ b/pyerrors/input/sfcf.py
@@ -650,7 +650,7 @@ def _read_append_rep(filename: str, pattern: str, b2b: bool, cfg_separator: str,
         return T, rep_idl, final_data
 
 
-def _get_rep_names(ls: list[str], ens_name: None=None, rep_sep: str ='r') -> list[str]:
+def _get_rep_names(ls: list[str], ens_name: Optional[str]=None, rep_sep: str ='r') -> list[str]:
     new_names = []
     for entry in ls:
         try:
@@ -665,7 +665,7 @@ def _get_rep_names(ls: list[str], ens_name: None=None, rep_sep: str ='r') -> lis
     return new_names
 
 
-def _get_appended_rep_names(ls: list[str], prefix: str, name: str, ens_name: None=None, rep_sep: str ='r') -> list[str]:
+def _get_appended_rep_names(ls: list[str], prefix: str, name: str, ens_name: Optional[str]=None, rep_sep: str ='r') -> list[str]:
     new_names = []
     for exc in ls:
         if not fnmatch.fnmatch(exc, prefix + '*.' + name):
diff --git a/pyerrors/obs.py b/pyerrors/obs.py
index 4ee81d10..45337053 100644
--- a/pyerrors/obs.py
+++ b/pyerrors/obs.py
@@ -233,7 +233,7 @@ class Obs:
         else:
             fft = True
 
-        def _parse_kwarg(kwarg_name):
+        def _parse_kwarg(kwarg_name: str):
             if kwarg_name in kwargs:
                 tmp = kwargs.get(kwarg_name)
                 if isinstance(tmp, (int, float)):