Python gpt-2

import torch
from transformers import GPT2LMHeadModel, GPT2Tokenizer

model = _pretrained('gpt2')
tokenizer = _pretrained('gpt2')

input_text = 'Once upon a time'
input_ids = tokenizer(input_text, return_tensors='pt')['input_ids']

output = (input_ids, max_length=100, num_return_sequences=1)

output_text = (output[0], skip_special_tokens=True)
print(output_text)