How do I build a simple chatbot using Python and Flask?

<!-- BEGIN COPY / PASTE -->
    from flask import Flask, request, jsonify

    app = Flask(__name__)

    @app.route('/chat', methods=['POST'])
    def chat():
        user_input = request.json.get('message')
        # Simple logic to generate a response
        if user_input.lower() == "hello":
            response = "Hi there! How can I help you today?"
        else:
            response = "I'm not sure how to respond to that."
        return jsonify({'response': response})

    if __name__ == '__main__':
        app.run(debug=True)
    <!-- END COPY / PASTE -->