def files_to_image_frame(cls,
                             url,
                             sc,
                             class_num,
                             partition_num=-1,
                             bigdl_type="float"):
        """
        Extract hadoop sequence files from an HDFS path as ImageFrame
        :param url: sequence files folder path
        :param sc: spark context
        :param class_num: class number of data
        :param partition_num: partition number, default: Engine.nodeNumber() * Engine.coreNumber()
        """
        jvalue = callBigDlFunc(bigdl_type,
                               "seqFilesToImageFrame",
                               url,
                               sc,
                               class_num,
                               partition_num)
        return ImageFrame(jvalue=jvalue)
Extract hadoop sequence files from an HDFS path as ImageFrame
        :param url: sequence files folder path
        :param sc: spark context
        :param class_num: class number of data
        :param partition_num: partition number, default: Engine.nodeNumber() * Engine.coreNumber()