!pip install transformers
from transformers import AutoTokenizer, AutoModel
from torch.nn import functional as F
tokenizer = AutoTokenizer.from_pretrained('deepset/sentence_bert')
model = AutoModel.from_pretrained('deepset/sentence_bert')

sentence = 'Who are you voting for in 2020?'
labels = ['business', 'art & culture', 'politics']

# run inputs through model and mean-pool over the sequence
# dimension to get sequence-level representations
inputs = tokenizer.batch_encode_plus([sentence] + labels,
                                     return_tensors='pt',
                                     pad_to_max_length=True)
input_ids = inputs['input_ids']
attention_mask = inputs['attention_mask']
output = model(input_ids, attention_mask=attention_mask)[0]
sentence_rep = output[:1].mean(dim=1)
label_reps = output[1:].mean(dim=1)

# now find the labels with the highest cosine similarities to
# the sentence
similarities = F.cosine_similarity(sentence_rep, label_reps)
closest = similarities.argsort(descending=True)
for ind in closest:
    print(f'label: {labels[ind]} \t similarity: {similarities[ind]}')