docs: def add_file(self, src, dest=None):
          """Add the file at ``src`` to the archive.
  
          If ``dest`` is ``None`` then it is added under just the original
          filename. So ``add_file('foo/bar.txt')`` ends up at ``bar.txt`` in the
          archive, while ``add_file('bar.txt', 'foo/bar.txt')`` ends up at
          ``foo/bar.txt``.
  
          """
          dest = dest or os.path.basename(src)
          with open(src, 'rb') as fp:
              contents = fp.read()
          self.add_contents(dest, contents)