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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 save_ds9(output, filename):
 """Save ds9 region output info filename. Parameters output : str String containing the full output to be exported as a ds9 region file. filename : str Output file name. """


    ds9_file = open(filename, 'wt')
    ds9_file.write(output)
    ds9_file.close()