Андрей

for event in longpoll.listen():
    if event.type == VkBotEventType.MESSAGE_NEW and event.object.text.lower() == 'привет':
        peerID = event.object.peer_id
        send('Привет')

@bot.message_handler(func=lambda message: 'дима' in message.text.lower(), content_types=['text'])
def lalala(message):
    sti = open('stickers/sticker.webp', 'rb')
    bot.send_sticker(message.chat.id, sti)

can also take a file_id instead of a file.