Return a list of paths to search for plugins in

        The list is searched in order.

def _get_paths(self):
        """Return a list of paths to search for plugins in

        The list is searched in order."""
        ret = []
        ret += ['%s/library/' % os.path.dirname(os.path.dirname(__file__))]        
        
        ret += self._extra_dirs
        for basedir in _basedirs:
            fullpath = os.path.join(basedir, self.subdir)
            if fullpath not in ret:
                ret.append(fullpath)
        ret += self.config.split(os.pathsep)
        ret += self._get_package_path()
        return ret