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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 dummy_image(filetype='gif'):
 """ Generate empty image in temporary file for testing """

    # 1x1px Transparent GIF
    GIF = 'R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7'
    tmp_file = tempfile.NamedTemporaryFile(suffix='.%s' % filetype)
    tmp_file.write(base64.b64decode(GIF))
    return open(tmp_file.name, 'rb')