watch_prefix method skips event if its value is None

.gitignore

@@ -0,0 +1 @@
+__pycache__

etcd_wrapper.py

@@ -45,4 +45,8 @@ class Etcd3Wrapper(object):
     def watch_prefix(self, *args, value_in_json=False, **kwargs):
         r, _ = self.client.watch_prefix(*args, **kwargs)
         for event in r:
-            yield EtcdEntry(event, event.value, value_in_json=value_in_json)
+            # if e.value is None don't propagate its value
+            if event.value is None:
+                continue
+            event = EtcdEntry(event, event.value, value_in_json=value_in_json)
+            yield event