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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update(self, quiet=False, prefix='[polyglot_data] '):
 """ Re-download any packages whose status is STALE. """

    self.clear_status_cache()
    for pkg in self.packages():
      if self.status(pkg) == self.STALE:
        self.download(pkg, quiet=quiet, prefix=prefix)