title: *** KeyError: 'font-family' on replacing a html string into another html string
body: <p>I'm trying to read 2 html files, and one to another in python, but I'm getting this error:</p>
  
  <pre><code>*** KeyError: '                font-family'
  </code></pre>
  
  <p>This is my code:</p>
  
  <pre><code>with open ("/.../email-template.html", "r") as myfile:
          html_content=myfile.read().replace("\n", "")
  
  with open ("/.../product_info.html", "r") as myfile:
          product_info=myfile.read().replace("\n", "")
  
  html_content.format(products=product_info)
  </code></pre>
  
  <p>This is email-template.html that part that should be replaced:</p>
  
  <pre><code>...
  &lt;table role="presentation" aria-hidden="true" cellspacing="0" cellpadding="0" border="0" align="center" width="100%" style="max-width: 600px;"&gt;
  
                  {{products}}
  
                  &lt;!-- Clear Spacer : BEGIN --&gt;
                  &lt;tr&gt;
                      &lt;td height="40" style="font-size: 0; line-height: 0;"&gt;
                          &amp;nbsp;
                      &lt;/td&gt;
                  &lt;/tr&gt;
  ...
  </code></pre>
  
  <p>How can I fix this?</p>