code: def _make_autoenv(self, action):
          
          env = ('%s_%s' % (self.prog, action.dest)).upper()
          env = re.sub(self.env_scrub_re, '', env.strip())
          env = re.sub(self.env_flatten_re, '_', env)
          if re.match('^[0-9]', env):
              # Handle leading numbers.
              env = '_%s' % env
          return env
docs: Generate a suitable env variable for this action.  This is
          dependant on our subcommand hierarchy.  Review the prog setter for
          details.