on the compressor at the end of evaluation.
</blockquote>


<a name='sect-customizing-compressors'><h4>Customizing Compressors</h4></a>

<p>Compressor objects follow a protocol that makes it easy to create
  specialized data formats. The ZLIB data format is essentially the
  same as the DEFLATE format with an additional header and a trailing
  checksum; this is implemented by creating a new class and adding a
  few new methods to the generic functions below.

<p>For example, consider a new compressed data f