more updation

Author: Devmoni

SliderPuzzleActivity.py

@@ -373,7 +373,7 @@ def read_file(self, file_path):
         self.ui._thaw(json.read(session_data))
 
     def write_file(self, file_path):
-        session_data = json.dumps(self.ui._freeze())
+        session_data = json.write(self.ui._freeze())
         f = open(file_path, 'w')
         try:
             f.write(session_data)