__init__.py 文件源码

def atom(cls, nodelist):
        t = nodelist[1][0]
        if t == token.LPAR:
            if nodelist[2][0] == token.RPAR:
                raise SyntaxError("Empty parentheses")
            return cls.interpret(nodelist[2])
        msg = "Language feature not supported in environment markers"
        raise SyntaxError(msg)