code: def _set_arg_generic(self, argid, arg, cast=str):
          
          usable, filename, append = self._redirect_split(arg)
          if usable != "":
              self.curargs[argid] = cast(usable)
          if argid in self.curargs:
              result = "{}: '{}'".format(argid.upper(), self.curargs[argid])
              self._redirect_output(result, filename, append, msg.info)
docs: Sets the value of the argument with the specified id using the argument passed
          in from the shell session.