docs: def to_environ(self, environ, skip=()):
          """
          Serialize and write self to environ[self._envvar].
  
          Parameters
          ----------
          environ : dict-like
              Dict-like object (e.g. os.environ) into which to write ``self``.
          """
          environ[ensure_unicode(type(self).__name__)] = (
              ensure_unicode(self.to_base64(skip=skip))
          )