修复了 GVSDSDK 兼容层的小问题

gvsdsdk/fluent.py

@@ -207,6 +207,13 @@ class _ValuesResult:
     def exists(self):
         return self._qs.exists()
 
+    def __getitem__(self, key):
+        if isinstance(key, slice):
+            self._qs = self._qs[key]
+            return self
+        else:
+            return self._qs[key]
+
     def __iter__(self):
         return iter(self._qs)