paramlist  : var, paramlist
        paramlist  : var
        paramlist  :

def param_list(self):
        """
        paramlist  : var, paramlist
        paramlist  : var
        paramlist  :
        """
        params = []
        while self.cur_token.type == TokenTypes.VAR:
            params.append(Var(self.cur_token))
            self.eat(TokenTypes.VAR)
            if self.cur_token.type == TokenTypes.COMMA:
                self.eat(TokenTypes.COMMA)

        return FunctionSig(params)