very simple wsgi application(via class)

gistfile1.py

class App(object):
    def __init__(self, environ, start_response):
        self.environ = environ
        self.start_response = start_response

    def __iter__(self):
        status = '200 OK'
        response_body = "Hello World!"
        response_headers = [('Content-Type', 'text/plain'),
                            ('Content-Length', str(len(response_body)))]
        self.start_response(status, response_headers)
        yield response_body