chg: Test if json exists in cached method

pymisp/abstract.py

@@ -60,6 +60,8 @@ if sys.version_info < (3, 0):
         @staticmethod
         @cached(cache=LRUCache(maxsize=150))
         def _load_json(path):
+            if not os.path.exists(path):
+                return None
             with open(path, 'r') as f:
                 data = load(f)
             return data
@@ -80,6 +82,8 @@ else:
         @staticmethod
         @lru_cache(maxsize=150)
         def _load_json(path):
+            if not path.exists():
+                return None
             with path.open('r') as f:
                 data = load(f)
             return data

pymisp/mispevent.py

@@ -1177,9 +1177,9 @@ class MISPObject(AbstractMISP):
             self.update_not_jsonable('ObjectReference')
 
     def _load_template_path(self, template_path):
-        if not os.path.exists(template_path):
-            return False
         self._definition = self._load_json(template_path)
+        if not self._definition:
+            return False
         setattr(self, 'meta-category', self._definition['meta-category'])
         self.template_uuid = self._definition['uuid']
         self.description = self._definition['description']