'Return a true filesystem path for resource_name,
co-ordinating the extraction with manager, if the resource
must be unpacked to the filesystem.'

def get_resource_filename(self, manager, resource_name):

    overrides = self._get_overrides()
    if (overrides is not None):
        filename = overrides.get_filename(resource_name)
        if (filename is not None):
            return filename
    return pkg_resources.DefaultProvider.get_resource_filename(self, manager, resource_name)
