docs: def set_env(self, key, value):
          """Sets environment variables by prepending the app_name to `key`. Also registers the
          environment variable with the instance object preventing an otherwise-required call to
          `reload()`.
          """
          os.environ[make_env_key(self.appname, key)] = str(value)  # must coerce to string
          self._registered_env_keys.add(key)
          self._clear_memoization()