the error that appears is not implemented error in getitem

Question

#I tried to implement custom data generator using albumentations.I an getting getitem raise NotImplementedError

class DataGenerator(tf.keras.utils.Sequence):
def __init__(self, images, label,  augmentations, input_dim, batch_size=32, 
                 shuffle=True):
    self.images = images
    self.label = label
    self.augment = augmentations
    self.batch_size = batch_size
    self.input_size = input_size
    self.model_name = model_name
    self.shuffle = shuffle

def __len__(self):
    return int(np.ceil(len(self.images) / self.batch_size))

def _getitem__(self, index):
    indexes = self.indexes[index * self.batch_size: (index + 1) * self.batch_size]
    batch_y = np.array([self.label[k] for k in indexes])
    batch_x = [cv2.cvtColor(cv2.imread(self.images[k]), cv2.COLOR_RGB2BGR) for k in indexes]          
    return np.stack([self.augment(image=x)["image"] for x in batch_x], axis=0), np.array(batch_y)