from wsgiref.simple_server import make_server
import os
   ...
   ...
def app(environ, start_response):
    path_info = environ["PATH_INFO"]
    resource = path_info.split("/")[1] #I get no error here the split works totally fine.

class Myclass:


    def __init__(self, environ, start_response):
            self.environ = environ
            self.start = start_response
            self.status = "200 OK"
            #
            self.headers = []

    #headers = []
    def content_type(path):
        if path.endswith(".css"):
            return "text/css"
        else:
            return "text/html"


    def app(self):
        path_info = self.environ["PATH_INFO"]
        resource = path_info.split("/")[1] # Here now split returns NoneType