title: join() argument must be str, bytes, or os.PathLike object, not 'function' problem
body: <p>I am currently working on my first website, but I am experiencing some issues such as this one:</p>
  <p>join() argument must be str, bytes, or os.PathLike object, not 'function'.</p>
  <p>I think it has something to do with views.py but I don't really know how to solve it.</p>
  <p>Here's the code:</p>
  <pre><code>def translator_view(request):
  
      def translator(phrase):
          translation = &quot;&quot;
          for letter in phrase:
              if letter.lower() in &quot;a&quot;:
                  if letter.isupper:
                      translation = translation + &quot;U&quot;
                  else:
                      translation = translation + &quot;u&quot;
              elif letter.lower() in &quot;t&quot;:
                  if letter.isupper:
                      translation = translation + &quot;A&quot;
                  else:
                      translation = translation + &quot;a&quot;
              elif letter.lower() in &quot;c&quot;:
                  if letter.isupper:
                      translation = translation + &quot;G&quot;
                  else:
                      translation = translation + &quot;g&quot;
              elif letter.lower() in &quot;g&quot;:
                  if letter.isupper:
                      translation = translation + &quot;C&quot;
                  else:
                      translation = translation + &quot;c&quot;
          return translation
      return render(request, translator, 'main/translator.html')
  </code></pre>