Type can be replaced with {module, function, arguments} tuple, in this case Confex will use external function to resolve the type. Function must returns either {:ok, value} or {:error, reason :: String.t} tuple.
Coverage remained the same at 88.312% when pulling b67bf898a2fbd7dc1f5fdd4c569b238ace9383c0 on vip30:master into 20af6bbfa3fb621e267e2909e44a7ded7b7eaf99 on edgurgel:master.
According to https://github.com/Nebo15/confex,
Type can be replaced with {module, function, arguments} tuple, in this case Confex will use external function to resolve the type. Function must returns either {:ok, value} or {:error, reason :: String.t} tuple.
I modified the readme to prevent misunderstanding