'Return the absolute path for the file corresponding to the `obj.id`.
This is regardless of whether or not the file exists.'

def _get_filename(self, obj, base_dir=None, dir_only=False, extra_dir=None, extra_dir_at_root=False, alt_name=None, obj_dir=False):

    path = self._construct_path(obj, base_dir=base_dir, dir_only=dir_only, extra_dir=extra_dir, extra_dir_at_root=extra_dir_at_root, alt_name=alt_name, obj_dir=False, old_style=True)
    if (not os.path.exists(path)):
        return self._construct_path(obj, base_dir=base_dir, dir_only=dir_only, extra_dir=extra_dir, extra_dir_at_root=extra_dir_at_root, alt_name=alt_name)
