check if func is string befor hasattring it

saqc/funcs/rolling.py

@@ -201,7 +201,7 @@ def _hroll(
     frame = pd.DataFrame(
         views.reshape(views.shape[0], views.shape[1] * views.shape[2] * views.shape[3])
     )
-    if hasattr(pd.DataFrame, func):
+    if isinstance(func, str) and hasattr(pd.DataFrame, func):
         result = getattr(frame, func)(axis=1)
     else:
         result = frame.apply(func, axis=1)