Remove unnecessary comparaison ('== True' or '!= None')

Author: xinshen

app/notifiers/webhook_client.py

@@ -32,7 +32,7 @@ def notify(self, messages, chart_file):
 
         data = {'messages': json.dumps(messages)}
 
-        if chart_file != None and os.path.exists(chart_file):
+        if chart_file and os.path.exists(chart_file):
             files = {'chart': open(chart_file, 'rb')}
 
             if self.username and self.password: