flask.py

class Flask:
    def __init__(self, import_name):
        self.import_name = import_name
        self.route_mapping = {} # empty dict to store all the route mapping
        
    def route(self, route_name): # parameterized decorator
        def wrapper(view_func):
            self.route_mapping[route_name] = view_func
            return view_func # here we are just returning the original function not modifying it
        return wrapper 
    
    # just making this function to demonstrate a server request from WSGI server
    def get_response_for_this_route(self, route_name):
        try:
            return self.route_mapping.get(route_name)()
        except TypeError as e:
            return '404 requested url not found!'
        
        
app = Flask(__name__)

@app.route('/')
def home():
    return 'this is home page'

@app.route('/signin')
def home():
    return 'this is signin page'

#----------let's test the web app-------
print(app.get_response_for_this_route('/'))
print(app.get_response_for_this_route('/signin'))
print(app.get_response_for_this_route('/route that does not exists'))