[xml] xmlSetExternalEntityLoader in python api

[dunk <dunk dunkfordyce co uk>]

hello,
        i need to use to xmlSetExternalEntityLoader from python but it appears
to be missing. I attempted to edit the xml api file but to no avail.
Could this be added please?

I tried adding this:
  <function name='xmlSetExternalEntityLoader' file='python'>
                        <return type='void'/>
                        <arg name='loader' type='pythonObject'/>
        </function>

but importing libxml2 from python then results in a missing symbol error
complaining about libxml_xmlSetExternalEntityLoader. Are there any docs
about how to use this file?

thanks for any help
dunk