Failed when using exit_json to get the return value

Hi! Friends, I know we can get successful returns calling module.exit_json, so I using the code below in my custom module to get some returns:

`

return_args = dict(
hello=hello, changed=changed, msg=msg, test=test
)
module.exit_json(**return_args)

`

But after the module executed, I can not see the returns.
In fact, I can see the returns if I use ansible-playbook to call the module using the option -v.

Have you ever seen this problem before? or can you give me some advices on this issue? thanks very much.