The -a argument to Flask?
Your link is from 0.11 version. But if you go to this link (which is 0.12 version of flask), it is missing. This commit should justify the reason it is not available :)
Your link is from 0.11 version. But if you go to this link (which is 0.12 version of flask), it is missing. This commit should justify the reason it is not available :)