fix syntax

[xqbumu]

No description provided.

[coveralls]

Coverage decreased (-0.2%) to 90.061% when pulling 31609a4 on xqbumu:patch-1 into 412b434 on casbin:master.

[hsluoyz]

Hi @xqbumu ,

the missing ] is intended, this example shows how Casbin handles the parsing error in model file.

[xqbumu]

@hsluoyz I finally got it, so I closed it