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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 init_app(self, app):
 """Initializes your mail settings from the application settings. You can use this if you want to set up your Mail instance at configuration time. :param app: Flask application instance """

        state = self.init_mail(app.config, app.debug, app.testing)

        # register extension with app
        app.extensions = getattr(app, 'extensions', {})
        app.extensions['mail'] = state
        return state