title: python how to append to file in zip archive
body: <p>If I do something like this:</p>
  
  <pre><code>from zipfile import ZipFile 
  
  zip = ZipFile(archive, "a")  
  
  for x in range(5):
      zip.writestr("file1.txt", "blabla")
  </code></pre>
  
  <p>It will create an archive with 5 files all named "file1.txt". What I want to achieve is having one compressed file to which every loop iteration appends some content. Is it possible without having some kind of auxiliary buffer and how to do this?  </p>