class Dp:
    def __init__(self, act, param):
        self.act = act
        self.param = param
        self.answers = {
            'request': {'imie': "welcomemsg"}
        }
        
    def identify(self):
        req = self.answers.get(self.act)
        response = req.get(self.param[0]) if not req is None else "null"
        return response if not response is None else "null"