Store the session from CGI/AIS systems. AIS system session has a variable `schedule_id` coming along, in order to align the attribute

A class that mimic the behavior of javascript's built-in Web API URL class in a pythonic way.

A container that store all the sessions by visa_type and places, along with thread safe methods to manipulate it.

An in-memory broadcaster backend. Maintaining an event queue that publish every incoming event. There is no channel distinguishment a

**Global** listener for mongodb connection pooling https://pymongo.readthedocs.io/en/stable/api/pymongo/monitoring.html

A class that mimic the behavior of javascript's built-in Web API URLSearchParam class in a pythonic way.

Global variable class.

A class that contains methods for sending notifications visa emails and other social media platforms.

MongoDB operations for storing: 1. Email subscription - a one-to-few relationship. Comparing to the previous JSON based TuixueDB,

An abstraction represent a U.S. Embassy or Consulate

A bundle of network requests and util functions.

MongoDB operations for storing: 1. All fetched visa status by (visa_type, embassy_code), *only successful fetching* 2. Overview of av