minor bugfix with apply and strings

dios/dios.py

@@ -591,7 +591,7 @@ class DictOfSeries:
                 s = func(self._data.at[c].values if raw else self._data.at[c], *args, **kwds)
                 new.append(s)
                 try:
-                    need_dios = True if isinstance(s, pd.Series) or len(s) > 1 else need_dios
+                    need_dios = True if not _is_scalar(s) else need_dios
                 except TypeError:
                     pass