title: "Invalid Filter" error for my custom Django template filters but not any other filters
body: <p>I have a python file in my Django project which contains a custom template tag and a custom template filter. </p>
  
  <p>My custom tag uses <code>template.loader.get_template()</code> to load another template file. This worked great... until I added my custom filter to the loaded template.</p>
  
  <p>Now I get a Django "Invalid Filter" <code>TemplateSyntaxError</code> exception. Looking at the call stack, Django is unable to load my template filter. </p>
  
  <p>Here's where things get weird.  I can use my custom filters from another template. I can use any other filter inside the template loaded by my custom tag. But I can't use my own filter inside my own custom tag.</p>
  
  <p>The obvious cause of this would be not loading my custom tag/filter file inside my template HTML, but I am correctly loading it. (because when I don't load it, I'll get a different error -- "invalid block tag")</p>
  
  <p>I'm running Django 1.2.3 on Python 2.7.</p>
  
  <p><em>[BTW, I finally found the answer myself, but it took me several hours and I wasn't able to find the answer anywhere on stackoverflow or google, so I'm going to answer my own question so others won't have to waste as much time as I did]</em></p>