def initAlgorithm(self, config):
        """
        Parameter setting.
        """
        self.addParameter(
            QgsProcessingParameterMultipleLayers(
                self.INPUT_LAYERS,
                self.tr('Input Layers'),
                QgsProcessing.TypeVectorAnyGeometry
            )
        )

        self.addParameter(
            QgsProcessingParameterString(
                self.FILTER,
                self.tr('Filter')
            )
        )

        self.modes = [self.tr('Append to existing filter with AND clause'),
                      self.tr('Append to existing filter with OR clause'),
                      self.tr('Replace filter')
                      ]

        self.addParameter(
            QgsProcessingParameterEnum(
                self.BEHAVIOR,
                self.tr('Behavior'),
                options=self.modes,
                defaultValue=0
            )
        )

        self.addOutput(
            QgsProcessingOutputMultipleLayers(
                self.OUTPUT,
                self.tr('Original layers with assigned styles')
            )
        )