need help with solving a simple captcha about cbl-js HOT 1 OPEN

var cbl = new CBL({
    character_set: "0123456789",
    blob_min_width: 5,
    blob_min_height: 8,
    blob_max_width: 10,
    blob_max_height: 12,
    pattern_width: 8,
    pattern_height: 10,
    allow_console_log: true,
    perceptive_colorspace: true,
    exact_characters: 4,
    blob_console_debug: true,
    blob_debug: "debugSegmented"
});

cbl.train("0635.png");
cbl.train("2971.png");
cbl.train("3996.png");
cbl.train("6755.png");
cbl.train("8976.png");

var saveModel = function() {
    cbl.condenseModel();
    cbl.sortModel();
    cbl.visualizeModel("visualizeModel");
    cbl.saveModel();
}