':return: çšæ·æåäžæ¬¡æŽ»åšçæ¶éŽïŒè¿ååŒäžº unix æ¶éŽæ³
:rtype: int'

@property
def last_activity_time(self):

    self._make_soup()
    act = self.soup.find('div', class_='zm-profile-section-item    zm-item    clearfix')
    return (int(act['data-time']) if (act is not None) else (-1))
