How to specify PuppetDB hostname in Puppet function?

[JuniperSpring]

On the command line I can specify the PuppetDB host:
puppet query nodes '...' --host 'puppetdb.example.com'

How do I specify the host when using a puppet function in a puppet manifest?

Thanks!

[Erik Dalén]

At the moment this is unsupported other than changing the puppetdb config file.