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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dispatch_request(self, environ, start_response):
 """Dispatch an incoming request."""

        # set up all the stuff we want to have for this request.  That is
        # creating a request object, propagating the application to the
        # current context and instanciating the database session.
        self.bind_to_context()
        request = Request(environ)
        request.bind_to_context()

        # get the current action from the url and normalize the page name
        # which is just the request path
        action_name = request.args.get("action") or "show"
        page_name = u"_".join([x for x in request.path.strip("/").split() if x])

        # redirect to the Main_Page if the user requested the index
        if not page_name:
            response = redirect(href("Main_Page"))

        # check special pages
        elif page_name.startswith("Special:"):
            if page_name[8:] not in pages:
                response = page_not_found(request, page_name)
            else:
                response = pages[page_name[8:]](request)

        # get the callback function for the requested action from the
        # action module.  It's "on_" + the action name.  If it doesn't
        # exists call the missing_action method from the same module.
        else:
            action = getattr(actions, "on_" + action_name, None)
            if action is None:
                response = actions.missing_action(request, action_name)
            else:
                response = action(request, page_name)

        # make sure the session is removed properly
        return ClosingIterator(response(environ, start_response), session.remove)