Fixed lint errors

src/bitmessagekivy/baseclass/addressbook.py

@@ -52,7 +52,7 @@ class AddressBook(Screen, HelperAddressBook):
             self.ids.scroll_y.scroll_y = 1.0
             where = ['label', 'address']
             what = self.kivy_state.searching_text
-        
+
         xAddress = ''
         self.ids.tag_label.text = ''
         self.queryreturn = list(reversed(
@@ -76,7 +76,8 @@ class AddressBook(Screen, HelperAddressBook):
             listItem.theme_text_color = "Custom"
             listItem.text_color = ThemeClsColor
             image = os.path.join(
-                self.kivy_state.image_dir, "text_images", f"{avatar_image_first_letter(item[0].strip())}.png"  # noqa: E999
+                self.kivy_state.image_dir, "text_images",
+                f"{avatar_image_first_letter(item[0].strip())}.png"  # noqa: E999
             )
             message_row.ids.avater_img.source = image
             listItem.bind(on_release=partial(self.addBook_detail, item[1], item[0], message_row))

src/bitmessagekivy/baseclass/addressbook_widgets.py

@@ -7,7 +7,7 @@ from kivymd.uix.button import MDRaisedButton
 from kivymd.uix.dialog import MDDialog
 
 
-class HelperAddressBook:
+class HelperAddressBook():
     """Widget utilities for Addressbook."""
 
     @staticmethod