<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def report_progress(stream=None):
 """Report progress from any currently installed reporters. Args: stream: The text stream (default: sys.stderr) to which progress will be reported. """

    if stream is None:
        stream = sys.stderr
    for reporter in _reporters:
        reporter(stream)