review = df['review_cleaned'].iloc[0]

batch_encoder = tokenizer.encode_plus(
    review,
    max_length = 512,
    padding = 'max_length',
    truncation = True,
    return_tensors = 'pt')

print('Batch encoder keys:')
print(batch_encoder.keys())

print('nAttention mask:')
print(batch_encoder['attention_mask'])