how does HTTPServer work in python code example

Example 1: python httpserver

python -m http.server 8000 --bind 127.0.0.1

Example 2: how does HTTPServer work in python

def run(server_class=HTTPServer, handler_class=S, addr="localhost", port=8000):

    server_address = (addr, port)               
    httpd = server_class(server_address, handler_class) 
    httpd.serve_forever()