code: def handle_command_exit_code(self, code):
          
          ca = self.call_args
          exc_class = get_exc_exit_code_would_raise(code, ca["ok_code"],
                  ca["piped"])
          if exc_class:
              exc = exc_class(self.ran, self.process.stdout, self.process.stderr,
                      ca["truncate_exc"])
              raise exc
docs: here we determine if we had an exception, or an error code that we
          weren't expecting to see.  if we did, we create and raise an exception