def init_app(self, app):
self.init_config(app)<EOL>self.wrap_errorhandler(app)<EOL>app.extensions['<STR_LIT>'] = _InvenioPagesState(app)<EOL>return app.extensions['<STR_LIT>']<EOL>
Flask application initialization.

        :param app: The Flask application.
        :returns: The :class:`invenio_pages.ext.InvenioPages` instance
            initialized.