Process completed with exit code 1.

System.stacktrace/0 outside of rescue/catch clauses is deprecated. If you want to support only Elixir v1.7+, you must access __STACKTRACE__ inside a rescue/catch. If you want to support earlier Elixir versions, move System.stacktrace/0 inside a rescue/catch

variable "tags" is unused (if the variable is not meant to be used, prefix it with an underscore)

unused alias Sandbox