Add some type hints

Author: stevenyoungs

gramps/gui/selectors/selectperson.py

@@ -20,6 +20,13 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #
 
+# -------------------------------------------------------------------------
+#
+# Standard python modules
+#
+# -------------------------------------------------------------------------
+from __future__ import annotations
+
 # -------------------------------------------------------------------------
 #
 # internationalization
@@ -101,7 +108,7 @@ def _local_init(self):
         self.setup_configs("interface.person-sel", 600, 450)
         self.tree.connect("key-press-event", self._key_press)
 
-    def get_window_title(self):
+    def get_window_title(self) -> str:
         return _("Select Person")
 
     def get_model_class(self):