[unmatched closing character][}]

Hello Experts,

I'm a newbie. A warning message displayed after config verify was run. Below is the line caused the warning:

..

set json_start [string first "{" $payload]

..

After config verify "tmsh load /sys config verify" ran, the console displaying the following warning:

There were warnings:

/Common/test_irule_v1:314: warning: [unmatched closing character][}]

What have I missed? What is the correct syntax for "{"?

Thanks much in advance.