Fix two small bugs

- Fix a bug that the level of the character can exceed the max level
- Fix a bug that the response is incorrect when upgrading the characters by `generic core`

latest version/core/character.py

@@ -25,6 +25,7 @@ class Level:
         if exp >= Constant.LEVEL_STEPS[self.max_level]:
             self.exp = Constant.LEVEL_STEPS[self.max_level]
             self.level = self.max_level
+            return None
 
         a = []
         b = []

latest version/server/user.py

@@ -100,7 +100,7 @@ def character_exp(user_id, character_id):
         core.amount = - int(request.form['amount'])
         core.item_id = 'core_generic'
         character.upgrade_by_core(user, core)
-        return success_return({'user_id': user.user_id, 'character': [character.to_dict], 'cores': user.cores})
+        return success_return({'user_id': user.user_id, 'character': [character.to_dict()], 'cores': user.cores})
 
 
 @bp.route('/me/save', methods=['GET'])  # 从云端同步