Fixed typo

pattrmm.py

@@ -362,7 +362,7 @@ def settings(self):
                     print(f'''Invalid order by setting "{invalid_order_by}".
                           Order by field '{invalid_order_by}' found. Using '{order_by}'.''')
                     logging.warning(f'''Invalid order by setting "{order_by}", falling back to default {default_order_by}''')
-                    if order_by not in possible fields:
+                    if order_by not in possible_fields:
                         print(f'''{order_by} is not a valid option. Using default.''')
                         self.order_by = default_order_by
             except KeyError: