def METHOD_NAME(self, image):
    if image:
        image_node = MaterialNode(self.material_system, pyrpr.MATERIAL_NODE_IMAGE_TEXTURE)
        image_node.set_input(pyrpr.MATERIAL_INPUT_DATA, image)
        self.color_node.set_input(pyrpr.MATERIAL_INPUT_COLOR, image_node)
    else:
        self.color_node.set_input(pyrpr.MATERIAL_INPUT_COLOR, 1.0)