<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def open_in_composer(self):
 """Open in layout designer a given MapReport instance. .. versionadded: 4.3.0 """

        impact_layer = self.impact_function.analysis_impacted
        report_path = dirname(impact_layer.source())

        impact_report = self.impact_function.impact_report
        custom_map_report_metadata = impact_report.metadata
        custom_map_report_product = (
            custom_map_report_metadata.component_by_tags(
                [final_product_tag, pdf_product_tag]))

        for template_path in self.retrieve_paths(
                custom_map_report_product,
                report_path=report_path,
                suffix='.qpt'):

            layout = QgsPrintLayout(QgsProject.instance())

            with open(template_path) as template_file:
                template_content = template_file.read()

            document = QtXml.QDomDocument()
            document.setContent(template_content)

            # load layout object
            rwcontext = QgsReadWriteContext()
            load_status = layout.loadFromTemplate(document, rwcontext)

            if not load_status:
                # noinspection PyCallByClass,PyTypeChecker
                QtWidgets.QMessageBox.warning(
                    self,
                    tr('InaSAFE'),
                    tr('Error loading template: %s') % template_path)

                return

            QgsProject.instance().layoutManager().addLayout(layout)
            self.iface.openLayoutDesigner(layout)