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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 post_create_app(cls, app, **settings):
 """Automatically register and init the Flask Marshmallow extension. Args: app (flask.Flask):
 The application instance in which to initialize Flask Marshmallow upon. Kwargs: settings (dict):
 The settings passed to this method from the parent app. Returns: flask.Flask: The Flask application that was passed in. """

        super(MarshmallowAwareApp, cls).post_create_app(app, **settings)

        marsh.init_app(app)

        return app