def check_valid(self): if self.color is None and self.texture is None: xmlr.on_error("Material has neither a color nor texture.")
def check_valid(self): if self.color is None and self.texture is None: xmlr.on_error("Material has neither a color nor texture")
def check_valid(self): if self.color is None and self.texture is None and not Material.error_already_displayed: Material.error_already_displayed = True xmlr.on_error("Material has neither a color nor texture\n")