title: Replace headers by bold in HTML with python
body: <p>I have some HTML text like this one:</p>
  <pre><code>'&lt;H1 LANG=&quot;es-ES&quot; CLASS=&quot;western&quot; STYLE=&quot;text-indent: -0.5cm; line-height: 100%&quot;&gt;&lt;FONT FACE=&quot;Arial, sans-serif&quot;&gt;&lt;FONT SIZE=3&gt;some_text_here&lt;/FONT&gt;&lt;/FONT&gt;&lt;/H1&gt;'
  </code></pre>
  <p>within a larger HTML text. I want to automatically identify all such headers and change them to simple bold text:</p>
  <pre><code>'&lt;B LANG=&quot;es-ES&quot; CLASS=&quot;western&quot; STYLE=&quot;text-indent: -0.5cm; line-height: 100%&quot;&gt;&lt;FONT FACE=&quot;Arial, sans-serif&quot;&gt;&lt;FONT SIZE=3&gt;some_text_here&lt;/FONT&gt;&lt;/FONT&gt;&lt;/B&gt;'
  </code></pre>
  <p>Using regular expressions are not the best because sometimes the header start and end are on different lines.</p>