>>> parse_form_request("123456",{"nonce": 1451122677, "msg": "helllo", "code": 0, "sign": "DB30F4D1112C20DFA736F65458F89C64"})
        <Storage {'nonce': 1451122677, 'msg': 'helllo', 'code': 0, 'sign': 'DB30F4D1112C20DFA736F65458F89C64'}>

def parse_form_request(api_secret, request):
    """
        >>> parse_form_request("123456",{"nonce": 1451122677, "msg": "helllo", "code": 0, "sign": "DB30F4D1112C20DFA736F65458F89C64"})
        <Storage {'nonce': 1451122677, 'msg': 'helllo', 'code': 0, 'sign': 'DB30F4D1112C20DFA736F65458F89C64'}>
    """
    if not check_sign(api_secret, request):
        raise SignError(u"message sign error")

    return Storage(request)