bugfix typo in variable

signalbot.py

@@ -214,7 +214,7 @@ def send_a(message, receiver, attachment):
         elif type(receiver) is list:
             signal.sendGroupMessage(message, [attachment], receiver)
     except Exception as ex:
-        log.error(f'Send Message with attachment Exception:"{ex}"", message="{message}", receiver="{receiver}", attachments="{attachments}"')
+        log.error(f'Send Message with attachment Exception:"{ex}"", message="{message}", receiver="{receiver}", attachments="{attachment}"')
 
 
 def help_func(receiver, message, groupInfo):