:return: whether we are inside DomTerm
        :rtype: bool

def is_domterm(cls):
        """
        :return: whether we are inside DomTerm
        :rtype: bool
        """
        import os
        if cls._is_domterm is not None:
            return cls._is_domterm
        if not os.environ.get("DOMTERM"):
            cls._is_domterm = False
            return False
        cls._is_domterm = True
        return True