## 1.15.4 The PythonWeb Middleware Components

The `web.wsgi` module contains middleware components to make use of all the functionality of the Python Web Modules.

All PythonWeb WSGI middleware components are classes which take another WSGI middleware component or an application as the first argument. Middleware components usually add entries to the `environ` dictionary so that the application can use their functionality by using values from the dictionary.

The subsequent arguments configure how the middleware behaves. The documentation for the `web.wsgi.cgi` module is a good starting point.