class DataGenerator(Sequence):
    'Generates data for Keras'
    def __init__(self, list_IDs, labels, image_path, mask_path,
    to_fit=True, batch_size=32, dim=(256,256),
    n_channels=1, n_classes=10, shuffle=True):
        'Initialization'
        self.list_IDs = list_IDs
        self.labels = labels
        self.image_path = image_path
        self.mask_path = mask_path
        self.to_fit = to_fit
        self.batch_size = batch_size
        self.dim = dim
        self.n_channels = n_channels
        self.n_classes = n_classes
        self.shuffle = shuffle
        self.on_epoch_end()