'Accept ``environ`` and ``start_response``; create a
:term:`request` and route the request to a :app:`Pyramid`
view based on introspection of :term:`view configuration`
within the application registry; call ``start_response`` and
return an iterable.'

def __call__(self, environ, start_response):

    response = self.execution_policy(environ, self)
    return response(environ, start_response)
