Youtube extension for Python-Markdown

Python-Markdown docs
Flask-Markdown docs

Replacing:

[youtube]https://www.youtube.com/watch?v=udlMSe5-zP8[youtube]

with youtube embed code

<div class="youtube">
  <iframe src="https://www.youtube.com/embed/moPtwq_cVH8" frameborder="0" allowfullscreen class="video"></iframe>
</div>

Extension source code