Select multiple target variables in keras tensorflow - python-3.x

Question

I am trying to follow a kaggle kernel for BERT implementation :
https://www.kaggle.com/hiromoon166/save-bert-fine-tuning-model
But i am not able to select target variables. I have to select multiple target variables as my y variable as it is a multi-label classification.
This is the line of code i am stuck on:
train_lines, train_labels = train_df['comment_text'].values, train_df.target.values
def convert_lines(example, max_seq_length,tokenizer):
max_seq_length -=2
all_tokens = []
longer = 0
for i in range(example.shape[0]):
tokens_a = tokenizer.tokenize(example[i])
if len(tokens_a)>max_seq_length:
tokens_a = tokens_a[:max_seq_length]
longer += 1
one_token = tokenizer.convert_tokens_to_ids(["[CLS]"]+tokens_a+["[SEP]"])+[0] * (max_seq_length - len(tokens_a))
all_tokens.append(one_token)
print(longer)
return np.array(all_tokens)
nb_epochs=1
bsz = 32
dict_path = os.path.join(BERT_PRETRAINED_DIR, 'vocab.txt')
tokenizer = tokenization.FullTokenizer(vocab_file=dict_path, do_lower_case=True)
print('build tokenizer done')
train_df = pd.read_csv('../input/jigsaw-unintended-bias-in-toxicity-classification/train.csv')
train_df = train_df.sample(frac=0.01,random_state = 42)
#train_df['comment_text'] = train_df['comment_text'].replace({r'\s+$': '', r'^\s+': ''}, regex=True).replace(r'\n', ' ', regex=True)
train_lines, train_labels = train_df['comment_text'].values, train_df.target.values
print('sample used',train_lines.shape)
token_input = convert_lines(train_lines,maxlen,tokenizer)
seg_input = np.zeros((token_input.shape[0],maxlen))
mask_input = np.ones((token_input.shape[0],maxlen))
print(token_input.shape)
print(seg_input.shape)
print(mask_input.shape)
print('begin training')
model3.fit([token_input, seg_input, mask_input],train_labels,batch_size=bsz,epochs=nb_epochs)
Please help me understand how to select target variables here?