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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 get_random_filename(content_type=None):
 """Get a pseudo-random, Planet-looking filename. planet-61FPnh7K planet-V8ELYxy5.tif :returns: a filename (i.e. ``basename``) :rtype: str """

    extension = mimetypes.guess_extension(content_type or '') or ''
    characters = string.ascii_letters + '0123456789'
    letters = ''.join(random.sample(characters, 8))
    name = 'planet-{}{}'.format(letters, extension)
    return name