<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_cached_path( self, field_name, path_or_url, download_if_missing=False, overwrite=False):
 """ Get the local path for a possibly remote file, invoking either a download or install error message if it's missing. """

        if len(field_name) == 0:
            raise ValueError("Expected non-empty field name")
        if len(path_or_url) == 0:
            raise ValueError("Expected non-empty path_or_url")
        return self.download_cache.local_path_or_install_error(
            field_name=field_name,
            path_or_url=path_or_url,
            download_if_missing=download_if_missing,
            overwrite=overwrite)