<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _progress(bytes_received, bytes_total, worker):
 """Return download progress."""

        worker.sig_download_progress.emit(
            worker.url, worker.path, bytes_received, bytes_total)