code: def cache_dir() -> str:
          
          if config.VENDOR is None:
              raise RuntimeError("modelforge is not configured; look at modelforge.configuration. "
                                 "Depending on your objective you may or may not want to create a "
                                 "modelforgecfg.py file which sets VENDOR and the rest.")
          return os.path.join("~", "." + config.VENDOR)
docs: Return the default cache directory where downloaded models are stored.