code: def QA_user_sign_in(username, password):
      
      #user = QA_User(name= name, password=password)
      cursor = DATABASE.user.find_one(
          {'username': username, 'password': password})
      if cursor is None:
          QA_util_log_info('SOMETHING WRONG')
          return False
      else:
          return True
docs: 用户登陆
      不使用 QAUSER库
      只返回 TRUE/FALSE