Fix get_data method to correctly check keys in ConfigManager data structure

src/metar_navigate/utils/config_manager.py

@@ -64,7 +64,7 @@ class ConfigManager(metaclass=SingletonMeta):
             tomli_w.dump(self.__data, f)
 
     def get_data(self,key):
-        if key in self.__data.items():
+        if key in self.__data.keys():
             return {key:self.__data[key]}
         else:
             return None