[Zope] ZPT file reader

Hello all I am trying to make an Application using external Python code and ZPT. In the examples I have, DTML is used and those files are read using HTMLFile() or DTMLFile(). What is the appropriate method for reading ZPTs? BTW Where can I find the API documenation for looking this up? I could not find anything on the Zope web site. Any help is appreciated, thanks Andre