docopt/docopt — pull request #166 by alanjds (2013-12-18 20:19:00+00:00)
Title: [FIX] "TypeError: unsupported operand type(s) for +" when something is not str

Got an issue on https://github.com/opdemand/deis CLI, but seems to be related to naive concatenation of parameter of DocoptExit.__init__()

This should fix the issue.