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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 accept(self):
 """Handler for when OK is clicked."""

        input_path = self.input_path.text()
        input_title = self.line_edit_title.text()
        input_source = self.line_edit_source.text()
        output_path = self.output_path.text()
        if not output_path.endswith('.tif'):
            # noinspection PyArgumentList,PyCallByClass,PyTypeChecker
            QMessageBox.warning(
                self,
                tr('InaSAFE'),
                tr('Output file name must be tif file'))
        if not os.path.exists(input_path):
            # noinspection PyArgumentList,PyCallByClass,PyTypeChecker
            QMessageBox.warning(
                self,
                tr('InaSAFE'),
                tr('Input file does not exist'))
            return

        algorithm = 'nearest'
        if self.nearest_mode.isChecked():
            algorithm = 'nearest'
        elif self.inverse_distance_mode.isChecked():
            algorithm = 'invdist'
        elif self.use_ascii_mode.isChecked():
            algorithm = 'use_ascii'

        # Smoothing
        smoothing_method = NONE_SMOOTHING
        if self.numpy_smoothing.isChecked():
            smoothing_method = NUMPY_SMOOTHING
        if self.scipy_smoothing.isChecked():
            smoothing_method = SCIPY_SMOOTHING

        # noinspection PyUnresolvedReferences
        QgsApplication.instance().setOverrideCursor(
            QtGui.QCursor(QtCore.Qt.WaitCursor)
        )

        extra_keywords = {}
        if self.check_box_custom_shakemap_id.isChecked():
            event_id = self.line_edit_shakemap_id.text()
            extra_keywords[extra_keyword_earthquake_event_id['key']] = event_id

        current_index = self.combo_box_source_type.currentIndex()
        source_type = self.combo_box_source_type.itemData(current_index)
        if source_type:
            extra_keywords[
                extra_keyword_earthquake_source['key']] = source_type

        file_name = convert_mmi_data(
            input_path,
            input_title,
            input_source,
            output_path,
            algorithm=algorithm,
            algorithm_filename_flag=True,
            smoothing_method=smoothing_method,
            extra_keywords=extra_keywords
        )

        file_info = QFileInfo(file_name)
        base_name = file_info.baseName()
        self.output_layer = QgsRasterLayer(file_name, base_name)

        # noinspection PyUnresolvedReferences
        QgsApplication.instance().restoreOverrideCursor()

        if self.load_result.isChecked():
            # noinspection PyTypeChecker
            mmi_ramp_roman(self.output_layer)
            self.output_layer.saveDefaultStyle()
            if not self.output_layer.isValid():
                LOGGER.debug("Failed to load")
            else:
                # noinspection PyArgumentList
                QgsProject.instance().addMapLayer(self.output_layer)
                iface.zoomToActiveLayer()

        if (self.keyword_wizard_checkbox.isChecked()
                and self.keyword_wizard_checkbox.isEnabled()):
            self.launch_keyword_wizard()

        self.done(self.Accepted)