chatbot with Machine Learning

with open('intents.json') as file:
    data = json.load(file)
    
training_sentences = []
training_labels = []
labels = []
responses = []


for intent in data['intents']:
    for pattern in intent['patterns']:
        training_sentences.append(pattern)
        training_labels.append(intent['tag'])
    responses.append(intent['responses'])
    
    if intent['tag'] not in labels:
        labels.append(intent['tag'])
        
num_classes = len(labels)