title: How to disable TOKENIZERS_PARALLELISM=(true | false) warning?
body: <p>I use pytorch to train huggingface-transformers model, but every epoch, always output the warning:</p>
  <pre><code>The current process just got forked. Disabling parallelism to avoid deadlocks... To disable this warning, please explicitly set TOKENIZERS_PARALLELISM=(true | false)
  </code></pre>
  <p>How to disable this warning?</p>